Not only is the Trojan Horse a colourful fiction, the existence of Homer himself has sometimes been doubted. It’s generally supposed that the great epics which go under Homer’s name, the Iliad and Odyssey, were composed orally, without the aid of writing, some time in the 8th Century BC, the fruit of a tradition of oral minstrelsy stretching back for centuries.
While the ancients had no doubt that Homer was a real bard who composed the monumental epics, nothing certain is known about him. All we do know is that, even if the poems were composed without writing and orally transmitted, at some stage they were written down in Greek, because that is how they have survived.
See other: Which Greek Legends Were Really True?