Jamshid al-Kashi

Ghiyath al-Din Jamshid al-Kashi (c. 1380–1429) was a Persian astronomer and mathematician born at Kashan. His early works included the Sullam al-sama, a treatise on celestial distances, and the Khaqani Zij, whose sine tables had unprecedented precision.

Invited to Samarkand by Ulugh Beg, who gathered scholars there, al-Kashi led work at the observatory, calculated pi to sixteen decimal places in 1424 and wrote the Key to Arithmetic using decimal fractions. He died at Samarkand in 1429; Ulugh Beg called him a scientist who could solve the hardest problems.