Ghiyāth al-Dīn Jamshīd Masʿūd al-Kāshī was a Persian astronomer and mathematician during the reign of Tamerlane. 1380 – July 1, 1429; died at about 49. Alive at the same time as Joan of Arc, Geoffrey Chaucer, Zheng He, Jan Hus, and Jan van Eyck. Wiki link