One of the last great Greek scholars,Ptolemy, applied geometry and trigonometry to astronomy about A.D 150. In a book, know as the Almagest, he presented a scheme for the motions of the heavenly bodies. He claimed that the earth was stationary and that it was in the center of a larger sphere around which the sun, stars, moon and planets revolved at uniform rates of speep. This model became the accepted theory of the solar system throughout the Middle Ages, both in the European and the Islamic world.