C. 1065 - 1136 Abraham bar Hiyya aka Savasorda (Spain – France)
Philosopher, astronomer, astrologer, and mathematician. He wrote numerous original works in Hebrew. These include Yesod ha-Tevunah u-Migdal ha-Emunah (The Foundation of Understanding and the Tower of Faith) an encyclopedia of math astronomy, optics and music . Books on astronomy include Sefer Tzurat HaAretz (Sphaera Mundi) (Form of the Earth) , and Hokhmat Ha'Chizayon, (in two parts ) a definitive work on astronomy and the calculation of the calendar. His Chibbur ha-Meshichah ve-ha-Tishboret (Treatise on Measurement and Calculation) (1116) was translated into Latin in 1145 by Plato of Tivoli as Liber Embadorum. It gave the area of a circle and helped introduce trigonometry to the west . He also translated many Arabic mathematical and scientific texts into Hebrew.