Like most towns hereabouts, Pennabilli sinks its roots into the ancient past. It was first inhabited by the Umbrians, Etruscans, and Romans, who used the area as a strategic link between the Tyrrhenian and Adriatic coasts.
Around the year 1000, a pervading sense of insecurity prompted the building of several castles; the embryonic settlements of Penna (on Mount Roccione) and Billi (Mount Rupe) grew around two of them. According to 14th-century sources, the epic story of the Malatesta family began here in 1004; in a few years, they would come to dominate the whole of Romagna.
In 1350, the independent communities of Penna and Billi joined forces to rebuild the town with the walls and gates that we still see today.
For over two centuries, the Malatesta, Montefeltro and de Medici families, and ultimately the Papal States, vied for control of the town, until 1572, when Pope Pius V moved the Diocese of Montefeltro from Monte Leo to Pennabilli, where it remains. Pius V later became the town’s patron saint.