Ulugh Beg

Ulugh Beg (1394 to 1449) was a Timurid ruler of Samarkand and one of the leading astronomers and mathematicians of the fifteenth century. Born at Soltaniyeh in Persia, he was the grandson of the conqueror Timur and was given Samarkand by his father Shah Rukh when he was sixteen. He used the city to build a centre of learning: a madrasah completed in 1420, where he appointed leading scientists such as al-Kashi and Qadi Zada, and an observatory begun in 1428. The work done there produced the Zij-i Sultani, a star catalogue published in 1437 that gives the positions of 992 stars, and tables of sines and tangents correct to at least eight decimal places, resting on his determination of the sine of one degree as the root of a cubic equation solved by numerical methods. After his father died in 1447 he could not keep power, and he was put to death at Samarkand at the instigation of his own son Abd al-Latif.