We know almost nothing about Thales of Miletus.
Later generations told many anecdotes about this wise man, but it is difficult to verify the reliability of these stories.
What seems certain, however, is that he predicted the solar eclipse of 28 May 585, which was remembered because the Lydian king Alyattes and the Median leader Cyaxares were fighting a battle on that day. Another reliable bit of information is that he did geometrical research, which enabled him to measure the pyramids.
However, his most important contribution to European civilization is his attempt to give rational explanations for physical phenomena.
Behind the phenomena was not a catalogue of deities, but one single, first principle.
Although his identification of this principle with water is rather unfortunate, his idea to look for deeper causes was the true beginning of philosophy and science. Thales died after 547.
