If up to now astronomy was above all associated with religious cults related to agriculture, it is thanks to the Greek philosophers of the first millennium BC (Thales, Pythagoras, Heraclides, Aristarchus), that we owe the foundations of astronomy. At the time of the poet Homer (8th century BCE) and the legendary Odyssey of Odysseus, the Greeks thought that the Earth was flat and surrounded by a river. Anaximander (circa 610-546 BCE) imagined instead that the Earth was cylindrical and surrounded by an ocean. But already at this time, according to some sources, Anaximander would have suggested that the Earth was spherical, which was confirmed by Thales of Miletus (624-547 BC) and Pythagoras (FL.560-480 BC). Thales of Miletus, philosopher, mathematician and political advisor, was one of the Seven Greek Sages. Familiar with schoolchildren for his famous theorem, this scholarly character was sufficiently initiated to astronomy to predict the solar eclipse of the year -585. Success that earned him all the more celebrity she ended a war. The Pythagoreans saw in the universe harmonious relations and perfect bodies. The Earth was spherical (although for many philosophers and the common man this theory was an aberration and remained so for a long time) and circular celestial movements. They stated that the planets were at distances equal to the intervals of the sounds of the lyre. The planets had to emit musical notes more and more serious according to their distance to the Earth. This harmony was called the music of the spheres.