Anaximander

Anaximander of Miletus was a Greek scholar of the sixth century BC, a pupil and probable successor of Thales in the Milesian school. None of his writings survive, but later authors record that he wrote on nature, the fixed stars and geometric surveying, and made a sphere and maps of the Greek and wider world. His importance for mathematics lies in his attempt to bring measurement and geometric reasoning into astronomy and geography. He pictured the earth as a cylinder floating in the middle of circling heavenly bodies, argued that the sun, moon and stars revolve around it, and gave proportions for their distances. He is also credited with inventing the solar gnomon, which fixes midday and the points of the compass. MacTutor counts these among the early Greek works that led to the study of trigonometry.