He was a grandson of the great conqueror and king, Timur (Tamerlane). Between 1417 and 1420, he built a madrasaon Registan Square in Samarkand (currently in Uzbekistan), and he invited numerous Islamic astronomers and mathematicians to study there.

In 1428, Ulugh Beg built an enormous observatory in Samarkand and with the instruments located in this observatory he composed a star catalogue consisting of 1018 stars, which is eleven fewer stars than are present in the star catalogue of Ptolemy.

In mathematics, Ulugh Beg wrote accurate trigonometric tables of sine and tangent values correct to at least eight decimal places.