The Ottoman Mosque Fallacy: Places of Worship Facing the Kaaba or “Monuments of Jihad”?
A. J. Deus has got it all hopelessly wrong: A critique of A. J. Deus, “Monuments of Jihad – The thought process of determining qibla orientations by Turks”, and “Raw Analysis Turkish Mosque Orientations ‘Monuments of Jihad’” and “Flipbook for Turkish Mosque orientations”.
Note of the Author: A critique of A. J. Deus, “Monuments of Jihad – The thought process of determining qibla orientations by Turks”, at www.academia.edu/37688323/ (text) and “Raw Analysis Turkish Mosque Orientations ‘Monuments of Jihad’”, at www.academia.edu/37688075/ (graphics), and “Flipbook for Turkish Mosque orientations” (data flipped), at www.academia.edu/37688045/, all accessed Nov., 2018.
If one wants to begin to understand the way in which historical mosques were laid out toward the Kaaba in Mecca or anywhere else, the best way is to study what medieval Muslim scholars wrote about the determination of the sacred direction (qibla). The medievals did not always use the methods we think they might have used to determine the qibla, and they did not have access to modern geographical coordinates. As a result, HISTORICAL qibla-values are not the same as MODERN ones. Or to put it another way, the directions for the qibla derived by Muslim scientists or chosen by Muslim architects centuries ago are not going to be the MODERN directions of Mecca. But we have useful aides. For example, for Ottoman cities we have an Ottoman list of qibla-directions for 90 cities in the Empire published 20 years ago. It might be a good idea to compare orientations of Ottoman mosques with that Ottoman list of qibla-values for Ottoman cities. Nobody has done that yet.
Simply comparing HISTORICAL mosque orientations with MODERN directions of Mecca (which were not available to medieval Muslims) is not a good idea. It exposes one to the danger of reaching all manner of absurd conclusions. For example, one might be tempted to think along with the amateur archaeologist Dan Gibson that early mosques face the MODERN direction of Petra (a place where there were no Muslims anyway) rather than the direction of Mecca; that silly idea has now been demolished although Gibson and his disciples will not stop believing in it because it suits their purpose. More recently, economist and amateur space archaeologist A. J. Deus in “Monuments of Jihad – The thought process of determining qibla orientations by Turks” (2018)* wants us to believe that Ottoman mosques are not aligned toward Mecca but rather toward specific places in Ukraine or Somalia or Armenia or Tunisia where the Ottomans were involved in military operations at the time just before the mosques were being built.
In this document, we try to penetrate the thought process of someone who has written about the orientations of Ottoman mosques without having a clue how the Ottomans determined the qibla.** Inevitably Deus has compared HISTORICAL mosque orientations with MODERN directions of Mecca. He wrongly thinks that accurate medieval mathematical tables giving the qibla for each degree of longitude (from Mecca) and each degree of latitude could have been used by Muslims in the past to determine the MODERN direction of Mecca! Not only is he clueless about medieval qibla determinations, but he has no background in Ottoman architecture and its history, Ottoman astronomy, mathematics and geography. He mistakenly thinks that the Ottomans when building a mosque wherever could orient it accurately with places no-one has ever heard of on the Empire’s frontier. The results of his labours are not only absurd but they are also insulting to those who built the mosques and to those who worship in them. This seems to have been his objective and he can certainly claim to have been successful. And he will find readers who are innumerate and have no time for Islam who will fall for this rubbish ‘hook, line and sinker ’, not least because, like the Petra nonsense, they will find it useful.
Mosques in the Turkish world do indeed constitute a particularly interesting sub-group of historical mosques as far as orientations are concerned. For these, the Ottoman list of qibla-values for Ottoman cities could be rather useful. If these mosque orientations do not correspond to the qiblas in this or other sources, we have to use our wits but at least we have access to a wide corpus of medieval Islamic material on astronomy, mathematics and geography to keep us in the ‘holy corridor ’ of truth and save us from making fools of ourselves.
“What is between the east and the west is a qibla.” Statement attributed to the Prophet Muḥammad.
Sinan handed over the building to Suleiman:
“Oh, my Sultan, I have built this mosque for you, which will stand upon the earth till the day of the Last Judgment.” Quoted in Péter Rabb, “Sinan – Architect of the Ottoman Empire”, p. 24.
“The calculation of mosque orientations must have been among the most strictly guarded military secrets [sic]. In consequence, modern researchers are in the dark about their methods [sic]. We now know that they were able to accurately compute the orientation toward distant places [sic].” Deus, p. 30.
One of my favourite places is the 16th-century Süleymaniye Mosque complex in Istanbul. It is not only a magnificent architectural masterpiece crowning one of the seven hills of the city but it includes one of the most beautiful and imposing mosques in the city. This is a sublime and peaceful place of worship, erected for people to pray facing the holiest sanctuary of Islam, the Kaaba in Mecca; this direction is called qibla in all languages of the Islamic commonwealth. The former madrasas or schools in the complex house an incredibly rich library of medieval Arabic, Persian and Turkish manuscripts essentially documenting much of the history of Islamic civilization, gathered from collections around the former Ottoman Empire and indeed from numerous mosque libraries all over Turkey. Together with the Topkapı Library and Istanbul University Library, it constitutes a goldmine for generations of historians.
I used to go to these libraries frequently when I worked in Cairo in the 1970s, following leads of one sort or another and finding enough new materials in Cairo and Istanbul but also in libraries from Princeton to Hyderabad and from Dublin to Taiz, to write a new chapter in the history of Islamic science. My chapter was called “Astronomy in the service of Islam”, and the reason nobody had written it previously was that most investigators in the history of Islamic science have been mainly interested in transmission – what the Europeans learned of Islamic science and what the Muslims preserved for ‘us’ of the Greek heritage –, not what the Muslims did for themselves.
Why did I do this? When I was still a graduate student, I discovered in an Arabic manuscript preserved in the Bibliothèque nationale de France a mathematical table compiled by Shams al-Dīn al-Khalīlī, an astronomer at the Umayyad Mosque in Damascus in the mid-14th-century. The table was unknown to the scholarly world and it blew my mind: one feeds the latitude of any locality along the top of the table and the longitude down the side of the table, and the entry in the table is the qibla in degrees and minutes, given with such astounding accuracy that we have not yet fathomed how the 2,880 entries in the table were computed. It was the discovery of this table, and of many other remarkable texts, tables, instruments, and maps, that has been my reward over half a century. These findings included some earlier qibla– tables located in Istanbul manuscripts. It was also at the Bibliothèque nationale de France that I found an Ottoman list of calculated qibla-directions for 90 cities in the Ottoman Empire. And then around 1990 I discovered three brass maps of the world centred on Mecca each with an ingenious grid preserving direction and distance to the centre. Some of my colleagues could not believe these remarkable maps from 17th-century Isfahan were an Islamic invention, especially when I stated that no European could have conceived them, but the mathematics underlying the grids is found already in Arabic texts on conic sections from 10th-century Baghdad and 11th-century Isfahan.
Some of these sources – scientific texts and instruments and legal texts – enabled me to explain some of the reasons why medieval mosques often face directions that we moderns sometimes find surprising. I dutifully published all of this material. I tried to draw wider attention to it in the articles “Ḳibla” and “Makka as the centre of the world” in the Encyclopaedia of Islam. I knew that historians of Islamic architecture, especially those who write about ‘sacred space’, have a singularly poor reputation regarding orientations and that they would be the last to recognize the potential importance of these materials. The scholars who were interested were those in ethnoastronomy and archeoastronomy, not least because the Islamic tradition is the only tradition in world history for which we have written sources. Ultimately, whether anybody other than my students was interested in these discoveries has always been for me of little consequence; in this way, I avoided inevitable disappointment. But this study is not about me, it is about mosques and what they can offer…
The Süleymaniye Library is a place where you could consult priceless manuscripts of works previously undocumented in modern times and where you would meet enthusiastic Turkish and international scholars with similar historical interests. And you could drink tea in the garden or enjoy a lamb- chop with green beans in one of the little kitchens overlooking the main mosque.
Imagine my surprise and horror at reading a few days ago absurd claims that the Suleymaniye Mosque was DELIBERATELY BUILT NOT FACING TOWARD MECCA and that it was DELIBERATELY BUILT AS A MONUMENT OF HOLY WAR, accurately facing directions associated with contemporaneous distant Ottoman military campaigns.
These claims are a slap in the face to anybody who knows anything about Islamic history and, in particular, Ottoman history, as they are to anybody who knows anything about historical mosques. They deliberately ignore completely everything that Muslim scholars have written over the centuries about the qibla, and they ignore everything my teachers and colleagues and I myself have written about the way the qibla was determined over the centuries. But, the reader may rest assured, this affront will be less painful when we establish that it is based on totally false assumptions and complete ignorance of Islamic customs regarding the building of mosques.
It is not my intention to discuss whether or not a given mosque was built to commemorate a particular victory somewhere. Deus would have certain mosques built before a victory occurred, which would have put considerable strain on the astrologers. My purpose here is simply to show that some of the mosques which Deus thinks point in all sorts of funny directions, actually face the Kaaba in Mecca. In fact, all the mosques he considered face the Kaaba. One just has to learn how this was achieved.
“The overwhelming guiding principle of academia rests on selective interpretation of traditions and wishful thinking.” Deus, p. 31.
As most readers should know, mosques are oriented toward Mecca. Certainly, every Muslim knows that. But actually, mosques are oriented toward the sacred Kaaba in Mecca, a direction called qibla in Arabic. There is, in medieval Islamic practice, a subtle but significant difference between facing a distant edifice and facing a distant city. This is something we moderns should take the trouble to learn if we want to begin to understand the orientation of historical mosques.
Mosques have been built facing the Kaaba for over 1,400 years. The way this was achieved varied according to time and place. The earliest methods involved astronomical alignments – the cardinal directions – north and south, sunrise and sunset at the equinoxes (east and west) – or solstitial directions (sunrise or sunset at the summer or winter solstices). The reason for this was that people wanted to face a distant edifice that was itself astronomically aligned. The major axis of the rectangular base of the Kaaba faces the rising of Canopus and the setting point of the stars of the Plough; the minor axis faces summer sunrise and winter sunset – for the latitude of Mecca these two axes happen to be perpendicular. Whether it was planned that way we shall never know; what we do know is that it is that way and that this has been of importance to Muslims over the centuries.
From the 9th century onwards the Muslims had access to geographical coordinates and they developed trigonometric and geometric methods for finding the qibla, towards a ‘point’ on the terrestrial globe, Mecca. But throughout history, the Muslims have used different methods for finding the qibla, which are documented in treatises on the sacred law, folk science, astronomy, mathematics, and geography. In particular, Muslims developed sacred geography with the world divided into sectors around the Kaaba, with each sector facing a segment of the perimeter of the Kaaba. Such simple approximate notions were used alongside the mathematically-computed qiblas, whose accuracy of course depended on the accuracy of the available geographical coordinates, longitude and latitude, which were not always satisfactory.
To take a given historical mosque orientation and say this is in error, or this is not facing Mecca, overlooks the fact that we can never know how the orientation was decided upon unless we are told in some treatise (which we can believe or not). Particularly if one knows nothing about the ways in which Muslims determined the qibla over the centuries it is rather arrogant to make any pronouncements. In all cases, we cannot expect that the qibla used for some mosque will be the same as the MODERN qibla except by coincidence. So, to pronounce, based on orientations alone, that a given mosque doesn’t even face Mecca, or that it deliberately faces some other locality, is not a good idea. Even if the qibla was calculated by a competent mathematician or astronomer, it might be derived using an approximate formula rather than an exact one, and it will surely have to be based on medieval geographical coordinates: the result would not necessarily correspond to the MODERN qibla. So, under no circumstances should orientations of buildings erected hundreds of years ago be investigated using MODERN data. It is about ‘them’, not about ‘us’.
Misinterpretations of Orientations
The one aspect of Islamic architecture which historians have persistently neglected if not completely ignored is orientations. I could write a whole article on uninformed pronouncements about the orientation of Islamic religious architecture by ‘the specialists’. The latter boldly state this or that without having a clue about what people at the time thought was the qibla (which is not the MODERN qibla). These historians of Islamic architecture have opened the floodgates to the latest wave of fanatics who have just discovered that mosques do not actually face Mecca (in the MODERN sense) and who think that they can use this to their advantage.
Historical mosque orientations serve as a happy hunting ground for people with no idea about historical qibla determinations (or those who deliberately choose to ignore what is already known) and they will keep on coming up with all sorts of ridiculous theories. Usually, the folk proposing such theories will be comparing MEDIEVAL mosque orientations with MODERN qibla– directions.
One of my favourites is Ehsan Butt, who has shown, using orientations, that not a few European cathedrals were originally built as mosques. Marvin Mills has proposed that the city of Córdoba was built by people from Atlantis and that the Grand Mosque was built as an observatory. This is not much more absurd than what some professional historians of Islamic architecture have claimed, namely, that Grand Mosque, built by Syrian emigres and facing south, symbolized a sentimental attachment to the Umayyad Mosque in Damascus, which also faces south. Cute this is, but actually, the Mosque in Córdoba does not face south – it faces the deserts of Algeria and we know very well why.
In the last few years Dan Gibson, an amateur archaeologist without a clue how Muslims determined the qibla or how they thought they could face the Kaaba, has proposed that numerous mosques from the 7th to the 9th century from Al-Andalus to China accurately face the MODERN direction of the “rose-red city” of Petra rather than any direction toward Mecca. This goes against everything we know about Petra and about Islam, but Gibson happily finds a dozen references to Petra in the Qur’ān which nobody had ever noticed before. Of course, he does not seriously address the question of how these (imaginary) early Muslims in Petra could have been able to orient mosques precisely toward Petra but instead proposes that the early Muslims of/from Petra must have been scientifically advanced and particularly gifted at determining directions from one place to another, distant one, which is not a trivial mathematical problem on the surface of a sphere. Therefore, he needed to create a mythical scenario in which these early Muslims were wandering about with astrolabes and applying spherical trigonometry to any spherical triangle they encountered. However, astrolabes, introduced to Muslims in the 8th century, were used for many purposes but were not used for finding the qibla, and it was plane trigonometry that served as the first mathematical determinations of the qibla using simple approximate methods.
What I like most about Gibson’s theory is that he happily includes mosques erected on the foundations of former cardinally aligned Jewish and Roman temples as well as Christian churches facing east and no less on Roman orthogonal street-plans, either cardinally or solstitial aligned, and he finds that these are accurately facing Petra too. What I like least about it is that he has the audacity to encourage Muslims to now, on the strength of his discoveries, to abandon the “false” qibla toward Mecca and go back to the true qibla (my term) toward Petra. I have discussed Gibson’s scatterbrain theories elsewhere, but there are many people who will fall for them and many who will welcome them. So, what next?
Enter A. J. Deus
“The orientations of the Turkish mosques in this data collection unmask Islam of the Turk dynasts’ flavors as militarily aggressive in its core religious fabric. Most Turkish mosques of this data set are identified as Monuments of Jihad. Tradition of Mecca as a focal point for the Muslim prayer direction serves merely as a cover-up.” Deus, p. 30.
A splendid example of this kind of new approach to mosque orientations is a study entitled:
“Monuments of Jihad –
The thought process of determining qibla orientations by Turks”
and it is written by Amod Jason Deus (www.ajdeus.org). online on 1 Nov 2018, the day I finished a paper entitled “The Petra fallacy”. The author, by training an economist, previously wrote in a review of Gibson’s Qur’ânic Geography that:
“one can make a confident case that Petra has nothing to do with the emergence of Islam”.
With this I can agree most heartily; it is, of course, obvious. On the matter of the qibla, however, Deus has decided to go it alone, scorning all established scholarship on the subject to the extent of omitting any mention of it, and ignoring all historical evidence other than the mosques themselves. Alas, in his misunderstandings have produced a document that is as odious as it is presumptuous and insulting. Few have previously sought to penetrate the thought processes of the Turks, and Deus has got it very wrong. However, Ottoman Studies have progressed substantially in recent years, pleased to have been able to contribute.
All of what I have written about Gibson’s fixation on MODERN directions applies also to Deus, because neither of them is able to understand that medieval people didn’t use MODERN directions from one place to another. And Deus doesn’t understand that if the greatest scientist of medieval Islam was to calculate the qibla of any locality, his result would be mathematically correct but it would inevitably be different from the MODERN qibla because he would be using geographical coordinates that were inaccurate by modern standards. Is that really so hard to understand? One difference between Gibson and Deus is that in Gibson’s time (7th to early 9th centuries) nobody computed the qibla, and in Deus’ time (12th to 19th centuries) some did compute it, others simply adopted qiblas favoured by tradition. Another difference is that for Gibson’s mosques, textual evidence is later; for Deus’ mosques, textual evidence is either contemporaneous or later. What the two have in common beyond a common motive is that innumerate revisionists and other hapless souls will fall for their pronouncements. Deus is far less generous than Gibson in what he divulges, and the reader may well be annoyed that he gives neither the actual orientation of his mosques, nor the (MODERN) qibla for the locality in which they are situated, but occasionally he gives the divergence between the two, which is of no use to anybody. His information on the mosques is minimal, sometimes a location, the name of the mosque, and the date of completion. He is generous only in the military campaigns which he associates with each mosque, for which he merits no thanks. His information on the Ottoman campaigns is pathetic, especially when a vast literature is available, including a very useful atlas published almost 50 years ago that is still available.
Mosque orientations in the Turkish world
Of all the many authors who have written on Ottoman mosques, the vast majority ignore orientations altogether. They have opened the way to Deus. In this new study, our author has examined over 250 ‘Turkish’ mosques using Google Earth and compared their orientations, which are nowhere stated in his analysis (!), with MODERN directions toward Mecca, Medina, Axum (!), Nineveh (!), and wherever.
Deus does not mention the variety of medieval qibla determinations and is singularly weak on bibliography; in particular, there is nothing on Ottoman architecture, Ottoman astronomy or Ottoman astrology or Ottoman mathematics or Ottoman geography or Ottoman cartography or Ottoman sacred geography or Ottoman scientific treatises on the qibla or Ottoman legal texts on the qibla or Ottoman instruments displaying the qibla for cities all over the Empire or lists of qiblas of Ottoman cities. Deus appears never to have heard of Ottoman qibla-indicators, handy instruments which show the qiblas of hundreds of places in the Muslim world, including, of course, places in Anatolia and Ottoman provinces even in Europe; the qibla-directions shown on these were, however, not calculated, they were based on Ottoman schemes of sacred geography.
Since he does not reveal that he knows anything about the history of qibla– determinations in general, let alone in the Ottoman world, Deus is singularly ill-equipped to investigate Ottoman mosques. He does not state the orientation of a single mosque, only occasionally the deviation of that mosque to the MODERN qibla, which is of no HISTORICAL interest. He starts off by mocking certain medieval Muslim legal scholars who advocated an entire quadrant for acceptable qibla-directions, which was actually not a bad idea at the time, and which would ensure that every mosque that Deus has investigated was adequate, from the point of view of Islamic law, facing the Kaaba. The treatise on the legal aspects of facing the Kaaba by the 12th-century Egyptian legal scholar al-Dimyāṭī is the most detailed and the most sensible discussion of the subject by a legal scholar that I have come across; in addition, it is illustrated. He discusses facing the Kaaba straight on or facing the general direction of the edifice, stating that qibla within the quadrant about the former is acceptable. Islamic law is another topic that Deus knows nothing about, so he brands this particular pronouncement as being for “fools”. I actually thought al- Dimyāṭī’s pronouncement was rather clever.
Deus needs to create an Ottoman world in which everybody could find the qibla correctly for any locality in order that they would not use that qibla for their mosques. So he invents the myth everybody in Turkey had access to the universal qibla table of my friend, the 14th-century Damascus astronomer al- Khalīlī, from which one can find the qibla accurately for all practical purposes for all longitudes and latitudes in the Muslim world. He claims this was “published” in Damascus in 1365 and available all over the Ottoman Empire, whereas in fact still only three manuscript copies are known, all from late-14th-century Damascus. He neglects to inform his readers precisely what this table is or where he found it, and wrongly assumes that it was widely known over the centuries. But although this table gave mathematically accurate qibla-values it would not give the MODERN ‘accurate’ qibla because the medieval did not have MODERN, that is, ‘accurate’ geographical data at their disposal to feed into the table. Deus neglects to inform his readers how his Ottoman builders could have known the exact directions from places all over the Ottoman Empire where they wanted to build mosques toward specific frontier localities in Iran, Armenia, Crimea, Hungary, Serbia, Crete, Tunisia, Egypt, Hejaz, Yemen and Iraq. And if there ever had been a military campaign connection with any of these mosques, one might have expected a reference or two in the inscriptions within the mosques, but, of course, there is no such thing. And if there had ever been a mosque associated with a campaign we might have found a reference to this in an illustrated campaign itinerary report, but again, of course, we do not. Or one might never expect to find some Ottoman tables displaying such directions, whereas in fact, and unbeknown to Deus, we have only found an Ottoman table of calculated directional values for 90 cities in the Empire and – lo and behold! – the directions are toward Mecca and they correspond to some of the mosque orientations he has misinterpreted as not being toward Mecca.
The qiblas derived by medieval Muslim scholars were not the MODERN qiblas
One might think that any Turkish astronomer worth his salt could have calculated the qibla of his location to within a degree or two if he had wanted. His results would, of course, not necessarily correspond with the MODERN, ‘accurate’ qiblas because MODERN geographical coordinates were not available. Also, we cannot be sure that he would have applied any exact mathematical method. Deus appears not to know that the Ottoman, astronomers’ favourite texts were two 13th-century books that were widely taught in madrasas for centuries – al-Jaghmīnī’s, al-Mulakhkhaṣ fi ‘l-haya and Naṣīr al-Dīn al-Ṭūsī’s al-Tadhkira fī ʿilm al-hay’a, both are published with English translation and each proposed an approximate method for finding the qibla that was obviously less accurate than the exact method; the method dates probably from the 8th century and was used for over a millennium. The divergence between the results using these two methods and MODERN geographical data for Western Anatolia might be a few degrees, and even for Eastern Anatolia, the same might be true. So Deus’ astronomers would not have computed the qibla exactly (even by medieval standards); nor would they have been able to compute the directions of all the other places he imagines to be relevant, namely battlegrounds all around the borders of the Empire (since no geographical coordinates were available for any but the major cities). And if they used an approximate formula for finding the qibla, they would not be using a complicated exact formula to find the directions of battle-sites whose geographical coordinates they had never measured.
Furthermore, those who laid out mosques were not always in touch with the astronomers; rather, they would use astronomical alignments or qiblas derived from diagrams of sacred geography or traditional methods popular in the region or the standard approximate geometrical procedure / trigonometric formula which was widely used from the 8th century to the 19th. None of these methods are mentioned by Deus, who prefers to refer occasionally to al-Khalīlī’s universal qibla table but never asks what longitudes and latitudes the Ottomans would have used as arguments in such a table. To make myself clear, if one enters MEDIEVAL geographical coordinates into a medieval table that gives a mathematically accurate value of the qibla, then the qibla given by the table will not be the MODERN qibla. And one should keep in mind that medieval geographical coordinates, especially longitudes, were not particularly accurate. For example, Byzantine and Ottoman values even for the latitude of the capital Constantinople / Istanbul varied between 41° and 48°, Although most 15th-century Ottoman values were more appropriately in the range 41°-42°.
Deus’ stated premise is that (p. 6):
“The Turkish builders were able to orient mosques precisely toward Mecca – but they did not.”
Both of these claims are incorrect. First, there was no way an Ottoman astronomer, let alone a builder, could find the MODERN qibla. The words “precisely toward Mecca” mean for Deus nothing other than the MODERN qibla because he knows no other. Second, all of the mosques under discussion were oriented toward the Kaaba in ways Deus does not understand, some calculated using approximate mathematical methods, others using exact procedures, and others derived by folk astronomical techniques or using Ottoman sacred geography or simply relying on tradition. If any of these orientations agree with the modern qiblas of the localities in question, then it is by coincidence.
Innocent of any Ottoman mathematics, Ottoman astronomy and astrology, Ottoman geography and cartography, and of any Ottoman procedures or instruments for finding the qibla, Deus presents page after page / slide after slide with monotonous, presumptuous Besserwisserei, falsely believing that the orientations can be allowed to speak for themselves, completely out of all contexts except a military one.
Deus considers the Turkish mosques chronologically because the dates of construction of the mosques are important for him to link with Ottoman military campaigns. The point of the exercise seems essential to show how Turkish mosques are oriented in four directions, one (maybe) more or less toward Mecca (but not always), but backwards or sideways (and even forwards) also in directions that can be associated with Turkish military campaigns. Thus, Deus is happy to point out that some of his mosques face not only Mecca (maybe) but also toward goals of jihād such as Moldavia or Bulgaria or Iraq or Djibouti. He seems not to take very seriously the fact that the Ottoman Sultans were the guardians of the two sacred cities of Mecca and Medina and would have reacted strongly against anybody who deliberately erected a mosque other than in the direction of the Kaaba.
It is not in question that the Ottomans were rather active militarily. It is known that on festive occasions mosques in Istanbul associated with sultans were sometimes decorated with, amongst many other things, with panels bearing the name of the particular sultan and a list of their successful campaigns. Furthermore, we do hear of occasional excesses on the part of Furthermore, we do hear of occasional excesses on the part of Tunis, which were displayed in front of the mosque which bears his name (see below). This is a far cry from erecting a mosque in the direction of La Goulette.
One aspect that Deus has not pursued is the prowess of Turkish astrologers. They were always present to choose an auspicious day for laying the foundations of a new mosque, especially one associated with the Sultan. But many of Deus’ mosque-campaign associations occur before the campaign has achieved its goal.
 A reasonable, inspired account is in http://www.lonelyplanet.com/turkey/istanbul/attractions/suleymaniye-mosque/a/poi-sig/401910/360887, possibly written by Thomas Goltz, one of my former students at New York University, now an expert on Central Asia. The account mentions the Library only in passing.
 For a brief introduction to the Library see http://hazine.info/suleymaniye-library/. For more information on this and other libraries see İsmail E. Erünsal, A Survey of the history, development and organization of Ottoman foundation libraries, (Sources of Oriental languages and literatures 84, Turkish sources 74), Harvard University, Department of Near Eastern Languages and Literatures, 2008.
 Apart from reprints of my papers in the Variorum series – Islamic Mathematical Astronomy (1986/1993); Islamic Astronomical Instruments (1987/1995); Astronomy in the Service of Islam (1993); and Islamic Astronomy and Geography (2012) – the two main works dealing with this topic are World-maps for finding the direction and distance to Mecca – Innovation and tradition in Islamic science (Leiden, etc.: Brill & London: Furqan Foundation, 1999), and In Synchrony with the Heavens – Studies in astronomical timekeeping and instrumentation in medieval Islamic civilization (2 vols., Leiden, etc.: Brill, 2004-05). All of these materials are accessible on the site http://www.davidaking.academia.edu.
 See Clive N. Ruggles, ed., Handbook of archaeoastronomy and ethnoastronomy, 3 vols., New York, etc.,: Springer, 2015, which contains the following articles: King, “Astronomy in the service of Islam”, pp. 181-196; Clemency Montelle, “Islamic mathematical astronomy‘‘, pp. 1909-1916; Tofigh Heidarzadeh, “Islamic astronomical instruments and observatories‘‘, pp. 1917-1926; Petra G. Schmidl, “Islamic folk astronomy”, pp. 1927-1934; and Daniel Martin Varisco, “Folk astronomy and calendars in Yemen”, pp. 1935-1940.
 A complete bibliography of modern writings on medieval qibla determinations and mosque orientations is appended to my essay “The Petra fallacy”, on which see below.
 This was rediscovered almost 40 years ago. See Gerald S. Hawkins & David A. King, “On the astronomical orientation of the Kaaba”, Journal for the History of Astronomy 13 (1982), pp. 102-109, repr. in King, Astronomy in the Service of Islam, Aldershot & Burlington VT: Variorum, 1993, XII. The discovery was made about the same time by GSH from satellite images and by DAK from medieval Yemeni astronomical manuscripts: the results were the same, so we published them together.
The main audience for this discovery was the archaeoastronomers and ethnoastronomers. It turned out that the Islamic tradition of orientations was the only one in human history for which we have no documentation. See various relevant chapters in Clive N. Ruggles, Handbook of archaeoastronomy and ethnoastronomy, 3 vols., New York, etc., Springer, 2015: King, “Astronomy in the service of Islam‘, pp. 181-196; Clemency Montelle, “Islamic mathematical astronomy‘‘, pp. 1909-1916; Tofigh Heidarzadeh, “Islamic astronomical instruments and observatories‘‘, pp. 1917-1926; Petra G. Schmidl, “Islamic folk astronomy”, pp. 1927-1934; & Daniel Martin Varisco, “Folk astronomy and calendars in Yemen”, pp. 1935-1940.
 King, “The sacred direction in Islam: A study of the interaction of religion and science in the Middle Ages”, Interdisciplinary Science Reviews 10 (1985), pp. 315-328; and “The determination of the sacred direction in Islam”, in World-maps for finding the direction and distance to Mecca, ch. 2, pp. 47-127.
 King, article “Makka. iv. As centre of the world [sacred geography and orientation of mosques]”, in Encyclopaedia of Islam, 2nd edn., 13 vols., Leiden: E. J. Brill, 1960-1980, vol. VI, pp. 180-187, repr. in Astronomy in the Service of Islam, X; and idem, “The sacred geography of Islam”, in T. Koetsier and L. Bergmans, eds., Mathematics and the Divine – A Historical Study, Dordrecht: Elsevier, 2005, pp. 161-178, repr. in Islamic Astronomy and Geography, Aldershot & Burlington VT: Variorum, VIII.
Of some relevance to the topic of Ottoman mosque orientations is my paper “Some Ottoman schemes of sacred geography”, Proceedings of the II. International Symposium on the History of Turkish and Islamic Science and Technology, Istanbul, 1986, 2 vols., Istanbul: Istanbul Technical University, 1986, I, pp. 45-57, also article “Makka as centre of the world”, in Encyclopedia of Islam, 2nd edn., fig. 5.
 There is no reliable overview of the history of Islamic science. For a start, the reader might try the essays on different topics in Roshdi Rashed, ed. in collaboration with Régis Morelon, Encyclopedia of the History of Arabic Science, 3 vols., London & New York: Routledge, 1996. Works on Islamic geography are usually interested only in maps and they ignore mathematical geography. Likewise, the monumental opus of the late Fuat Sezgin (Mathematische Geographie und Kartographie im Islam … , 4 vols., Frankfurt, 2000-07) ignores Islamic sacred geography altogether.
On astronomy in general, which includes mathematical geography, see Carlo Alfonso Nallino, “[Islamic Astronomy]”, in Encyclopaedia of Religion and Ethics, James Hastings, ed., 12 vols., Edinburgh: T. & T. Clark, vol. 12 (1921), pp. 88-101; David A. King, “Islamic astronomy”, in Christopher Walker, ed., Astronomy before the Telescope, London: British Museum Press, 1996, pp. 143-174, repr. in Islamic Astronomy and Geography, I, also available on www.muslimheritage.com/article/islamic-astronomy; and Robert G. Morrison, “Islamic astronomy and astrology”, in Robert Irwin, ed., New Cambridge History of Islam, vol. 4, Cambridge, etc.: Cambridge University Press, 2010, pp. 589-613.
The scholar who inspired three generations of students in this field was E. S. Kennedy (1912-2009), on whom see Suhayl – International Journal for the History of the Exact and Natural Sciences in Islamic Civilisation 9 (2009-2010), pp. 185-214, available at www.ub.edu/arab/suhayl/. For some publications of the Beirut school, see Kennedy, Colleagues and Former Students, Studies in the Islamic Exact Sciences, David A. King and Mary Helen Kennedy, eds., Beirut: American University of Beirut, 1983.
Biographies of individual Muslim scientists’ biographies are available at The Biographical Encyclopedia of Astronomers, Thomas Hockey et al., eds., New York: Springer, 2007, available at http://islamsci.mcgill.ca/RASI/BEA/.
For a brief survey of Ottoman science see Salim Aydüz, “Ottoman contributions to science and technology”, at http://www.muslimheritage.com/article/ottoman-contributions-science-and-technology (accessed 2018). See also below on the publications of Ekmeleddin İhsanoğlu and his colleagues at IRCICA.
 Ehsan Butt, “Did Gothic cathedrals of Dark Age Europe begin as Islamic mosques?”, at http://www.arfaglobal.com/p/islamic-mosqe-cathedrals-of-europe.html (accessed 2017).
 Marvin H. Mills, The Origin of the Mosque of Cordoba: Secrets of Andalusia, Sarasota FL, privately distributed, 2006, printed Universe, 2007.
 Robert Hillenbrand, “The Great Mosque of Córdoba’’, an appendix to “‘The Ornament of the World’. Medieval Cordoba as a cultural centre”, in S. K. Jayyusi, ed., The Legacy of Muslim Spain, Leiden, New York & Cologne: Brill, 1992, pp. 112-135, esp. pp. 129-135. See now King, “The enigmatic orientation of the Great Mosque of Córdoba”, at davidaking.academia.edu.
 Dan Gibson, Early Islamic Qiblas: A Survey of mosques built between 1AH/622 C.E. and 263 AH/876 C.E. (with maps, charts and photographs), 296 pp., Vancouver BC: Independent Scholars Press, 2017, and now “Qibla Tool” (2018), available at http://thesacredcity.ca/data/index.html.
 King, “From Petra back to Mecca – From pibla back to qibla” (2017), available at www.davidaking.academia.edu, also www.muslimheritage.com/article/from-petra-back-to-makka. Since Gibson persists on writing about the significance of the MODERN directions of Petra for early Islamic mosques, I have written a further critique entitled “The Petra fallacy – Early Islamic mosques do face the Sacred Kaaba in Mecca but Dan Gibson does not know how or why” (2018), at davidaking.academia.edu. The latter includes a full biography of modern writings on medieval qibla determinations and mosque orientations.
 A. J. Deus, “Monuments of Jihad – The thought process of determining qibla orientations by Turks”, at http://www.academia.edu/37688323/(text) and “Raw Analysis Turkish Mosque Orientations ‘Monuments of Jihad’”, at www.academia.edu/37688075/ (graphics), and “Flipbook for Turkish Mosque orientations” (data flipped), at www.academia.edu/37688045/, all accessed Nov., 2018.
 King, “Astronomical alignments in medieval Islamic religious architecture”, Annals of the New York Academy of Sciences 385 (1982), pp. 303-312, repr. in Astronomy in the Service of Islam, XIII; idem, “The orientation of medieval Islamic religious architecture and cities”, Journal for the History of Astronomy 26 (1995), pp. 253-274, with a new version in In Synchrony with the Heavens, VIIa: 741-771; and idem, “The determination of the sacred direction in Islam”, in idem, World-maps for finding the direction to Mecca, ch. 2, pp. 47-127.
 Deus’ earlier writings on the qibla and orientations are his “Sura 2: Many qibla – The qibla in the Koran, Abu Lahab, and the birth of Islam” (2016), at http://www.academia.edu/28111367/, and “Orientation of structures in early Islam” (2016), at http://www.academia.edu/28103240/ Orientation of Structures in Early Islam. The latter already reveals the author’s penchant for investigating orientations SOLELY by means of MODERN maps incorporating MODERN geographical data and finding directions by MODERN methods. Obviously, nothing of any historical interest can be expected from such Spielerei.
 See Leslie Peirce, “Changing perceptions of the Ottoman Empire: The early centuries, Mediterranean Historical Review 19:1 (2004), pp. 6-28.
 With surveys of Ottoman astronomical timekeeping and regulation of the prayers; Ottoman sacred geography and instruments for finding the qibla; astronomy and instrumentation during the reign of Sultan Bāyazīt II and an analysis of the spherical astrolabe of Mūsà Jālīnūs (1480); and a catalogue of Ottoman astrolabes.
 The longitudes and latitudes in some 80 Islamic geographical and astronomical lists of localities with their positions, some 14,000 pairs of coordinates, are collected in E. S. Kennedy & Mary Helen Kennedy, Geographical coordinates of localities from Islamic sources, Frankfurt: IGAIW, 1987. Most of these tables do not give qibla-values alongside the coordinates. The ones that do are discussed and analyzed in King, World-Maps for finding the direction of Mecca.
 See Donald Edgar Pitcher, An historical geography of the Ottoman Empire from the earliest times to the end of the sixteenth century, with detailed maps to illustrate the expansion of the Sultanate, Leiden: E. J. Brill, 1972.
 Thus, for example, the article “Islamic architecture” on Wikipedia (https://en.wikipedia.org/wiki/Islamic_architecture), obviously written by a Westerner, contains a paragraph on the qibla and mosque orientation which is unexpurgated nonsense. The source for this was purportedly my 1995 article “The orientation of medieval Islamic religious architecture and cities”, which the author obviously had not read.
 Reliable introductions are in John D. Hoag, Islamic architecture, Milan: Electaarchitecture, 2004 and John Freely, A history of Ottoman architecture, Southampton & Boston: WITpress, 2011.
 The basic works, listing the available manuscript sources, are Ekmeleddin İhsanoğlu et al., Osmanlı astronomi literatürü tarihi – History of Astronomy Literature during the Ottoman Period, 2 vols., Osmanlı matematik literatürü tarihi – History of Mathematics Literature during the Ottoman Period, 2 vols.; and Osmanlı coğrafya literatürü tarihi – History of Geography Literature during the Ottoman Period, 2 vols., Istanbul: Research Centre for Islamic History, Art and Culture (IRCICA), 1997, 1999, 2000. The overviews in İhsanoğlu, Science, technology and learning in the Ottoman Empire, Aldershot & Burlington VT: Variorum, 2004, deal mainly with the later period and the introduction of Western science.
 On qibla-indicators, in general, see King & Ricard P. Lorch, “Qibla charts, qibla maps, and related instruments”, in J. B. Harley & David Woodward, eds., The History of Cartography, vol. 2, bk. I: Cartography in the Traditional Islamic and South Asian Societies, Chicago & London: University of Chicago Press, 1992, pp. 189-20; King, World-Maps for finding the direction of Mecca, pp. 89-124; and idem, In Synchrony with the Heavens, I: 94-99.
 King, In Synchrony with the Heavens, VII: 758 & 817, also article “Makka as centre of the world” in Encyclopaedia of Islam, 2nd edn., pls. 1-2.
 It would certainly have saved Muslims in North America a lot of wasted energy, for there are those who believe the qibla is north-east and those who believe it is south-east, and the decades-old controversy is not resolved.
 King, “al-Khalīlī’s qibla table”, Journal of Near Eastern Studies 34 (1975), pp. 81-122, repr. in idem, Islamic Mathematical Astronomy, London: Variorum, 1986, repr. 1993, XIII, also available at http://muslimheritage.com/article/al-khalili-spherical-astronomy. Deus’ comments on this table (p. 6), which conveniently omits to mention my 1975 article, are weird and confirm that he can handle neither scientific literature nor historical literature. He mentions that al-Khalīlī’s table is based on that of Ibn Yūnus, but these are tables for astronomical timekeeping, not for the qibla. He speculates about the existence of earlier qibla-tables, without knowing that these have all been published.
 Gülru Necipoğlu, “Religious Inscriptions on the Great Mosques of the Ottoman, Safavid and Mughal Empires”, Hadeeth Ad-Dar (Dar al-Athar al-Islamiyyah, Kuwait National Museum) 25 (2008), pp. 34-40.
 J. Michael Rogers, “Itineraries and town views in Ottoman histories”, in J. B. Harley & David Woodward, eds., The History of Cartography, vol. 2, bk. I: Cartography in the Traditional Islamic and South Asian Societies, Chicago & London: University of Chicago Press, 1992, pp. 228-255.
 As I wrote 20 years ago, there must be many more such lists in the vast sources still available for the study of Ottoman science. This particular one, from MS Paris BnF ar. 2544, fol. 106v, must be rather early because it is based on the standard locations of classical Islamic geographical tables with a few significant additions, namely, Larnaka, Belgrade, Sofia, Plovdiv, Rhodes, Skopje, Athens and Salonika. I have not investigated the entries because no longitudes and latitudes are given, but some entries, such as that for Cairo (see below), give the impression of being based on an exact mathematical procedure. See King, World-Maps for finding the direction to Mecca, pp. 149-161 & 456-477, esp. p. 461, no. 72.
 On Ottoman astronomical activity in Istanbul around 1500 see now Ahmet Tunç Şen, Astrology in the service of the Empire – Knowledge, prognostication, and politics at the Ottoman Court 1450s-1550s, PhD dissertation, University of Chicago, Department of Near Eastern Languages and Civilizations, 2016, and King, “Two spherical astrolabes from Tunis and Istanbul” (2018), esp. Ch. 7: “Sultan Bāyazīt II and his interest in astronomy”, available at davidaking.academia.edu.
 Sally P. Ragep, Jaghmīnī’s Mulakhkhaṣ – An Islamic Introduction to Ptolemaic astronomy, New York, etc.: Springer, 2016. pp. 165-169 & 277-278; and F. Jamil Ragep, Naṣīr al-Dīn al-Ṭūsī’s Memoir on astronomy (al-Tadhkira fī ʿilm al-hayʾa), Berlin & New York: Springer, 1993, vol. I, pp. 306-309 & vol. II, pp. 496-499. (The other method presented, namely, finding the azimuth of the sun when it is at the zenith of Mecca, is somewhat impractical.)
 King, “The earliest Islamic mathematical methods and tables for finding the direction of Mecca”, Zeitschrift für Geschichte der arabisch-islamischen Wissenschaften 3 (1986), pp. 82-149 & 4 (1987/88), p. 270, repr. in Astronomy in the Service of Islam, XIV. This paper analyzes materials from the 8th and 9th centuries, including simple approximate procedures and already sophisticated tables displaying the qibla as an approximate function of longitude and latitude difference from Mecca.
 The reason for this was that instead of bothering to measure the latitude, the Byzantines placed their capital in the 5th or 6th or even 7th climate, with corresponding latitudes 41°, 45° and 48°. See King, “[Notes on Byzantine astronomy]”, ISIS 82 (1991), pp. 116-118, and “Spherical astrolabes from Tunis and Istanbul” (2018), on davidaking.academia.edu. The climates (Arabic iqlīm, pl. aqālīm) were very important in ancient and medieval geography, but their influence has been underestimated in modern times. But the unhappy situation regarding the latitude of Constantinople resulted from an excess of reliance on the climates and total scientific incompetence on the part of the Byzantine astronomers who would favour latitudes other than 41°. Also, Islamic astrolabes from al-Andalus to Central Asia show latitudes for Constantinople in the range 41°-48°, but those with values in excess of 42° were relying on tradition.
 King, “Turkish tables for timekeeping”, Ch. 14 in In Synchrony with the Heavens, pp. 437-456. All known Ottoman astrolabes have the more realistic range 41°-42° for the latitude of Istanbul.
 One can follow the Ottoman campaigns on https://en.wikipedia.org/wiki/List_of_Ottoman_conquests,_sieges_and_landings
 Gülru Necipoğlu, The Age of Sinan: Architectural culture in the Ottoman Empire, Princeton NJ & Oxford: Princeton University Press, 2005, p. 67, and Selen Bahriye Morkoç, A Study of Ottoman narratives on architecture – Text, context and hermeneutics, PhD dissertation, University of Adelaide, 2006, p. 200.
 Necipoğlu, The Age of Sinan, p. 68, and Morkoç, Ottoman narratives on architecture, p. 201.
 On Ottoman astronomical activity in Istanbul around 1500 we have Ahmet Tunç Şen, Astrology in the service of the Empire – Knowledge, prognostication, and politics at the Ottoman Court 1450s-1550s (2016). None of Tunç’s astrologers was predicting military campaigns in order to erect a mosque somewhere.
* Available at www.academia.edu/37688323/ (text) and www.academia.edu/37688075/ (graphics), and “Flipbook for Turkish Mosque orientations” (data flipped), at www.academia.edu/ 37688045/, all accessed Nov., 2018.
** I tend to use the term ‘medieval’ in the context of Islamic science for the entire period from the 7th to the 19th century because traditional Islamic science continued to be practiced throughout this period. So medieval here means post-classical and pre-modern. From the 9th to the 15th century, the Muslims were the leaders in science, although thereafter Islamic science declined and eventually aspects of European science were introduced in the Muslim world. Also, in this paper, I refer to the mosques (mis)treated by Deus as ‘Ottoman’ even though some predate the Ottoman period. They are not ‘Turkish’ and some of them are not in ‘Turkey’ anyway. Likewise, there is no such thing as an Arab mosque or an Arabic mosque.