Ovid's Fasti, his poem on the Roman calendar, became especially influential during the fifteenth century as a guide to classical Roman culture. Ovid's treatment of mythological and astronomical lore, his investigation of anniversaries and customs, and his charting of monuments and history offered humanist poets and intellectuals an abundance of material to unravel. They could identify with Ovid as vates operosus, or hard-working seer-poet,...