Astrolabe of ‘Umar ibn Yusuf ibn ‘Umar ibn ‘Ali ibn Rasul al-Muzaffari

For an object produced during the medieval period, this astrolabe is unusually well documented. Its inscription attributes it to a Rasulid prince, 'Umar ibn Yusuf, a few years before he ascended to the throne (r. 1295–96). 'Umar compiled a number of scientific treatises, including one on the construction of astrolabes, an autographed version of which, preserved in Cairo, contains certifications by his teachers as to his competence as a maker of such devices and a description of this very piece.