Anaximander (610-546 BC) was born in Miletus [now in Turkey]. He is one of the earliest figures to have developed a philosophical theory of cosmology. He is said to have been a pupil or associate of Thales of Miletus, who maintained that all matter is made of water. Aniximander held rather that everything originated from the aperion, the ‘infinite’ or ‘unlimited’. This and eternal motion were the ultimate causes of the world. The Earth was considered a vertical cylinder, with the top face corresponding to the inhabited region, supported by nothing. He supposed it could have no tendency to move in any direction because it was equidistant from all things. Aniximander was therefore one of the first to enunciate a symmetry principle and a kind of conservation principle (motion was ‘eternal’) in a theory of the universe. He was also the first to develop an evolutionary view of living things, among them man.