Ovid

The Fasti works through the Roman year month by month, stopping at each festival to explain where it came from, and it is one of the best witnesses there is to Roman religious practice because it records rites whose meaning had already become obscure to Romans. At the Lemuria the head of the household rises at midnight, washes his hands, walks barefoot through the house throwing black beans over his shoulder without looking back, says nine times that with these he redeems himself and his, and then bangs bronze and tells the shades to leave. At the Parentalia the family attends to its own dead. At the Terminalia the boundary stone is garlanded and a sacrifice is made over it.

What makes the poem a good source is its habit of offering several explanations for one custom and refusing to choose. Ovid asks the gods, asks antiquarians, reports incompatible etymologies, and lets them stand. That is a nuisance for anyone wanting a single answer and a gift for anyone studying how a living religion carries practices it can no longer account for. Six books survive, covering January to June. Whether the second half was written and lost, or never finished, is not known, and the poem as we have it breaks off at midsummer.

The Metamorphoses runs from the first separation of the elements to the deification of Julius Caesar, fifteen books joined so that one story leads to the next without a break. It was not composed as a reference work and it became one. Almost every version of Daphne turning into the laurel, Narcissus at the pool, Arachne and the weaving contest, Actaeon and the hounds, Pygmalion and the statue, or Orpheus looking back, that a European reader has ever met, descends from this poem rather than from any earlier Greek source, because this is the version that stayed in circulation.

The medieval church could not simply drop it and did not try. Readers produced moralised Ovids, long commentaries in which each transformation is decoded as a Christian lesson, so that the poem could be taught while its content was neutralised, and the manuscripts of those commentaries are numerous. Renaissance painters worked from the same text, which is why so much of the mythological subject matter in European art follows his arrangement and his details. He himself was banished to the Black Sea in the year 8 by Augustus, for what he called a poem and a mistake, and never said plainly what the mistake was.

One further habit of the poem shaped what came after it. Ovid tells almost every story as a change of state, and the change is usually a punishment, a rescue or a consolation delivered by a god who is not much interested in the person it lands on. That framing made the material portable. A story about a girl turning into a tree carries no doctrine with it, so it could travel into a Christian culture as decoration, as moral example, or as subject matter for painting, in a way that the cult it came out of could not.