Maragheh

A city in the hills of northwestern Persia where Nasir al-Din al-Tusi persuaded his Mongol patron Hulagu, fresh from the sack of Baghdad, to build the greatest observatory of the age. Its instruments, library, and salaried astronomers made Maragheh the world center of mathematical science for a generation, and its planetary models reached, by routes still debated, as far as Copernicus.

Maragheh sat in the hills of Azerbaijan, and al-Tusi talked Hulagu into funding an observatory there after having survived the destruction of nearly everything else. It received a library, salaried staff, instruments larger than anyone had built before, and thirty years of systematic observation that produced new planetary tables. The mathematical devices worked out there to repair Ptolemy's models turn up later in Copernicus, though exactly how they travelled is still argued about.