Fakhr al-Din al-Akhlati belongs to the history of thirteenth-century mathematical learning and Maragha’s observatory. Research on its personnel and a modern edition of Nur al-Dalala provide specific evidence for his work.

White modern hemispherical enclosure with a triangular panel framework and open doorway at the Maragha observatory site
Modern enclosure at the Maragha observatory site, photographed by Nassim Hosseini on 1 April 2011. CC BY-SA 4.0 via Wikimedia Commons. This is a modern site photograph, not the medieval observatory’s original dome or a portrait of al-Akhlati. © Nassim Hosseini · 1 April 2011 · Wikimedia Commons · CC BY-SA 4.0. Resized without creative changes.

Name and dates: activity is not a death notice

The Hassan Bin Mohammed Center’s 2016 publication notice identifies the mathematician as Fakhr al-Din Abd al-Aziz ibn Abd al-Jabbar al-Khilati and uses the dates 1197–1282. [1] Those are the dates supplied by that publisher, not a newly established critical chronology. Al-Akhlati appears in research on Maragha’s thirteenth-century scientific personnel. [2] His association with the observatory around 1260 should not be turned into a death in 1260 or a claim that he was killed in the Mongol conquests.

Maragha and a team drawn from several cities

Christine Roughan dates the observatory’s foundation to 1259 under Hulagu and discusses Nasir al-Din al-Tusi’s account of its establishment. In the preface to the Zij-i Ilkhani, the personnel include Muayyid al-Din al-Urdi, Fakhr al-Din al-Khilati, Fakhr al-Din al-Maraghi and Najm al-Din Dabiran. Al-Khilati is associated there with Tiflis. [2] A place-name in a career narrative and a geographical nisba need not describe the same stage of someone’s life.

Observation, teaching and the library

Roughan’s study places observation alongside education and the movement of texts. The institution gathered more than astronomers: teachers, students, librarians, scribes and scholars of other subjects also formed part of its setting. Bar Hebraeus described studying in a library preserving Syriac, Arabic and Persian books. [2] This makes Maragha a connected scholarly environment. It does not make al-Akhlati the sole author of every discovery associated with the observatory or prove he taught every person who visited it.

What the Zij-i Ilkhani was for

Yavuz Unat’s TDV entry places al-Akhlati among the scholars associated with the observatory and describes the Zij-i Ilkhani as a work of astronomical tables. Its four divisions cover calendars; planetary positions and geographical coordinates; prayer times based on sunrise and sunset; and further astronomical questions. Trigonometric and star tables also feature. [3] These are concrete products of measurement and calculation. A team’s association with the project should be distinguished from a claim that each member composed the whole book.

Nur al-Dalala: a named mathematical work

The Center announced a 2016 edition of Nur al-Dalala, edited by Roshdi Rashed, under a subtitle concerning arithmetic algebra in the thirteenth century. Its notice describes an instructional work gathering results in arithmetic algebra and some number theory. [1] The announcement establishes an identifiable work and edition; it is not a substitute for reading every theorem in the edited volume. It also makes a blanket claim that all of al-Akhlati’s writings disappeared untenable.

Ahlat, the nisba and the modern photograph

Faruk Sümer’s TDV account locates Ahlat on Lake Van’s northwestern shore and describes it as the Ahlatshahs’ capital from the early twelfth century. [4] It should not be confused with the Shaddadid centres of Ganja and Ani. The nisba al-Khilati/al-Akhlati links a name to Ahlat; it does not establish ethnicity by itself. The photograph instead shows Maragha’s modern site enclosure, clearly separated from the medieval setting of his career. [5]

Sources and further reading

  1. Hassan Bin Mohammed Center for Historical Studies, announcement of the Nur al-Dalala edition edited by Roshdi Rashed, July 2016; author name, publisher’s dates and subject.
  2. Christine Roughan, Out of Maragha: Observations, Teachings, and Translations, Mediterranea 7 (2022), pp. 347–375; introduction and historical background, especially p. 349, note 2.
  3. Yavuz Unat, Zîc-i İlhânî, TDV İslâm Ansiklopedisi 44 (2013), p. 399; personnel, structure and tables.
  4. Faruk Sümer, Ahlat, TDV İslâm Ansiklopedisi (1989), geographical introduction and Ahlatshah period.
  5. Nassim Hosseini, Maragheh Observatory 01, 1 April 2011, Wikimedia Commons; photograph, CC BY-SA 4.0.