Xenophanes of Colophon was a Greek poet and thinker who lived in the 6th and 5th centuries BCE. Born in Ionia (modern-day Turkey), he left his homeland as a young man and spent most of his long life traveling and performing his poetry throughout the Greek world, eventually settling in Sicily and southern Italy. He is traditionally grouped among the earliest philosophers known as the Presocratics.

His surviving work consists of fragments of poems, which include satirical verses, elegies, and philosophical speculations. In these works, he is best known for his radical criticism of traditional Greek religion. He argued that the gods of Homer and Hesiod were imagined in human form, and instead proposed a single, supreme deity unlike mortals in body or thought. He also offered rational explanations for natural phenomena like rainbows and fossils, and he criticized the high social status given to athletes over wise individuals.

According to modern scholars, Xenophanes represents a crucial step from mythological storytelling toward philosophical inquiry. His ideas about a non-anthropomorphic god and his use of observation to explain the natural world influenced later major philosophers like Parmenides, Empedocles, Plato, and Aristotle. His life and fragmented writings provide a key early example of critical, rational thought about divinity, nature, and society.