C. 1065  1136 C.10651136 ABRAHAM BAR HIYYA aka Savasorda (Spain)
Philosopher, astronomer, astrologer, and mathematician. He wrote numerous original works in Hebrew. These include Yesod haTevunah uMigdal haEmunah (The Foundation of Understanding and the Tower of Faith) an encyclopedia of math astronomy, optics, and music. His definite work on astronomy Khochmat haChiza'yon consisted of two parts Tzurat haAretz veTavnit Kaddurei haRaki'a ("Form of the Earth and Figure of the Celestial Spheres ") and Kheshbon Mahalekhot haKokhavim ("Calculation of the Courses of the Stars parts of which were translated into Latin. His Chibbur haMeshichah vehaTishboret (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.
