Pietro Pileo di Prata (or da Prata) (Prata, c.1330- Rome, 1400) was an Italian bishop and Cardinal. He was a significant diplomat and go-between in the affairs of his times, and was nicknamed the ‘cardinal with three hats’, because of the vicissitudes of his cardinalate under three popes.
Urban VI sent him as a legate to Germany and Hungary. He criticized Urban, with Landolfo Maramaldo, and was deposed. He then went over to the camp of Avignon Pope Clement VII, for whom he acted as legate. He was reinstated by Pope Boniface IX in 1391, as bishop of Frascati. He may have become dean of the College of Cardinals in 1397, as the most senior Cardinal Bishop after the death of Philippe d'Alençon.