How and by whom were the Iliad and Odyssey composed and preserved?

Certain anticipations apart, the modern debate began in 1788 with the publication by Villoison of the scholia in the tenth-century manuscript of the Iliad, Venetus Marcianus Graecus 454. These marginal notes preserve substantial remnants of ancient scholarship on the poems, going back as far as third-century BC Alexandria and permitting inferences about the earlier state of the text. Starting from the premise that Homer lived in an illiterate age (a premise which, ironically enough, we now know to be false), and using the new evidence, F. A. Wolf in 1795 argued that the poems as we have them were put together by a compiler living long after Homer, who had been a simple singer of heroic lays. The game was then to detect by analysis of the poems which bits derived from the original Homer, and which bits from later bards or editors; of these epigoni most scholars working in the analytical tradition (Wolf himself excepted) had a low opinion. Their handiwork was betrayed by inconcinnities, inconsistencies and repetitions in the poems, allowing the scholar to determine which parts had been composed independently of each other and in what order; by these means a wonderful variety of theories emerged, dividing the poems up in different ways and placing 'Homer' at various points in their evolution. Nowadays critics tend to explain most of these irregularities by reference to the exigencies of oral performance.