Ovid's Fasti has been the centre of increasingly vigorous literary and historical study since 1978, but despite the flood of stimulating articles and monographs, there has been no English language commentary on any part of the text since Frazer's five splendid volumes published in 1929. This commentary on book iv is intended to make one of the most interesting months of Ovid's calendar available for undergraduate and graduate study. As far as possible I have incorporated the ideas and approaches of recent discussions on Augustan monuments and ideology, on the Augustan public calendar and on both early and Augustan religious practice.

The bulk of my research for this commentary was made possible by leave granted by Princeton University in 1994–5: during that time I was privileged to be the guest of the Department of Classics and Archaeology at the University of New England, Australia, and the Dipartimento di Filologia Latina, University of Pisa. The American Academy graciously awarded me a residency for October to December 1994: there the Librarian Christina Huemer and her staff made research a delight, and the Professor in Charge Malcolm Bell enabled me to walk the ground that Ovid trod and understand where I was standing. In 1995 and again in summer 1996 Pembroke College Cambridge generously welcomed me as a Visiting Scholar, and the Cambridge University Faculty of Classics offered me use of its library and enjoyment of its seminars.