Who they were
Tradition makes Homer a blind bard from Ionia, and seven cities — Chios and Smyrna among them — claimed him as their own. All of this is legend: no fact of his life can be verified.
What they did
The Homeric Question asks whether the epics were composed by one poet, by two, or by a long oral tradition; modern scholarship generally sees them as products of generations of oral formulaic poetry, written down around the 8th–7th century BC. The poems preserve a fusion of Mycenaean memories — boar’s-tusk helmets, places prominent in the Bronze Age — with the society of the later Iron Age: a poetic amalgam, not a chronicle.
Legacy
The epics formed the core of Greek education; Alexander the Great, according to ancient anecdote, slept with the Iliad under his pillow. As the starting point of Western literature, they have been read, translated, and reworked continuously for nearly three millennia.