Ulugh_Beg Ulugh Beg (Chaghatay/ - also Uluğ Bey, Ulugh Bek and Ulug Bek) (c. 1393 or 1394 in Sultaniyeh (Persia) October 27, 1449) was a Timurid ruler as well as an astronomer, mathematician and sultan. His commonly-known name is not truly a personal name, but rather a moniker, which can be loosely translated as "Great Ruler" or "Patriarch Ruler" and was the Turkic equivalent of Timur's Perso-Arabic title Amīr-e Kabīr.