The Roman patron god of gardens, viniculture, sailors and fishermen. He is portrayed wearing a long dress that leaves the genitals uncovered. The Romans placed a satyr-like statue of him, painted red and with an enormous phallus, in gardens as some kind of scarecrow, but also to ensure fruitfulness. The fruits of the fields, honey and milk were offered to him, and occasionally donkeys. He was very popular and in his honor the Priapea was written--a collection of 85 perfectly written poems, sometimes funny but usually obscene.
Originally, Priapus was a fertility god from Asia Minor, especially in Lampsacus on the Hellespont, and was the most important god of the local pantheon (see: the Greek Priapus). He was introduced in Greece around 400 BCE but never was very popular. Priapus' attribute is the pruning knife.