Cairo strengthens transregional scholarly exchange

The city's multilingual scholarly environment later supported translations and original work in arithmetic, algebra, geometry and astronomy.

Baghdad's planned circular form joined surveying, geometry, architecture and imperial symbolism in a major urban project.

Al-Azhar opened in Fatimid Cairo and developed into a long-lived institution of learning.

Alongside religious and linguistic studies, scholars taught inheritance arithmetic, astronomy, timekeeping and related mathematical subjects.

Al-Azhar shows how mathematics was transmitted through teaching communities rather than only through famous books and individuals.

The Abbasid caliph surrendered on 10 February 1258, followed by the sack of a city central to centuries of scientific exchange.

Libraries and institutions suffered catastrophic loss, although the familiar story that all books were thrown into the Tigris cannot be treated as a precise inventory.

Knowledge survived through manuscripts and scholars in Maragha, Damascus, Cairo, Central Asia and other centers, preventing a simple rise-and-collapse narrative.

The destruction of Abbasid institutions redirected scholars and resources, reshaping rather than ending mathematics in the Islamic world.

Pope Gregory XIII issued the bull Inter gravissimas. It reformed leap-year rules to bring the civil calendar closer to the solar year.