Pennabilli is the result of the union of two ancient castles, the castle of Billi, located on the cliff and the castle of Penna, located on Roccione. Initially it was a feud of the Carpegna, then it became the land of the Malatesta, before the family displaced toward Verrucchio and then to Rimini. In 1572, the seat of the Diocese of Montefeltro was finally transferred to Pennabilli from San Leo.