The author of The Iliad and The Odyssey. Probably.
Ancient tradition pictured him as a blind poet from Ionia (the Aegean coast of today’s Turkey and its islands), around the 8th century BC. Modern scholars mostly see “Homer” as a label: both poems grew out of a long oral tradition of improvised performance before being written down, in an artificial literary Greek mixing several dialects, and most think the two poems had different authors.
So the most famous poet in history may not have existed. The poems don’t care.