During the latter part of his life he is said to have lived in Magna Græcia, where he carried on his studies and made some of his great discoveries. He was a profound geometrician, and two great theorems, one still known as the Pythagorean, are ascribed to him. He propounded the doctrine that the earth is a planet of spherical form, and the sun the centre of the planetary system. His philosophy prescribed and taught a total abstinence from everything which had animal life, and temperance in all things, together with the subjection of the appetites of the body. By this strict discipline, he seems to have obtained almost complete control over the wills and minds of his followers, from whom he demanded the utmost docility. Preparatory to entering on his novitiate, the pupil was strictly examined by the master as to his principles, habits, and intentions. The tone of his voice, his manner of speaking, his walk, gestures, and the lines of his face and the expression of his eyes, were all carefully observed, and only if all these features were satisfactory was he admitted as a probationer. After this interview the master withdrew from the sight of the pupil, who could then enter on his novitiate of three and five, in all eight years, during which time he was not permitted to look on the master, but only hear him speak from behind a curtain, and he was enjoined to preserve the strictest silence. To add to his mystery and authority, Pythagoras is said to have hid himself during the day from his pupils, and was only visible to them after the night had come on. He is described as having a most imposing and majestic appearance, with a grave and awe-inspiring countenance. When he came forth he appeared in a long garment of the purest white, with his long beard flowing, and a garland upon his head. He allowed his followers to believe he was one of the gods, and he is said to have told Abaris that he resumed human form so that he might win the confidence of man. Doubtless, owing to his great attainments and his superiority to the men of his time, he considered himself more divine than human, and he claimed to have miraculous endowments. Those who were not of his followers ascribed the stories related of him to magic, which probably, like other philosophers, he studied. Among other stories which tradition has handed down concerning Pythagoras are the following: He professed to have appeared in different ages in various human forms—first as Æthalides, the son of Mercury, and then as Euphorbu, who slew Patroclus at the siege of Troy, and as other individuals also.