Xenophanes was a Greek philosopher, poet, and social and religious reformer. He was born around 570 or 565 BC, and lived to an extreme age (died around 470 BC). Much of our knowledge of his views comes from his surviving poetry, which criticized and satirized a wide range of ideas, including the belief in the pantheon of gods and the Greeks' veneration of athleticism.
A native of the city of Colophon, Xenophanes went to Elea in 536 BC, and there founded the Eleatic school of philosophy. The Eleatic school taught that the universe, contrary to all appearance, was an unchanging and homogeneous whole. Xenophanes also held the Pythagorean chair of philosophy for much of his life.
Xenophanes rejected the common belief in many gods, as well as the idea that the gods resembled humans in form. One famous passage ridiculed the idea by claiming that, if oxen were able to imagine gods, then those gods would be in the image of oxen. Instead the Eleatic school developed the idea of just one omnipotent and omnipresent god (Monism / Pantheism), who is identical with the whole universe.
He also wrote that poets should only be able to tell stories about the gods which were socially uplifting, a view which foreshadowed Plato's ideas.It is said that Xenophanes concluded from his examination of fossils that water once must have covered all of Earth's surface.
Note: There is some controversy over many aspects of Xenophanes' life, including whether he can be properly characterized as a philosopher. Some claim that he can better be described as a poet with a few philosophical tendencies.