Standing upon a hill in the Sacco valley, Ferentino is thought to have been built by the Volsci people and later conquered by the Ernici, who erected the mighty wall around the highest part of the historic centre. The walls were built between the 7th and 6th centuries BC and have a series of twelve gates through which you reach an elevated scenic area. A dominant feature of the acropolis is the Romanesque cathedral, built in the 10th century and rebuilt seven centuries later. Inside the church there are striking decorations, such as the medieval Cosmatesque floor and other contemporary architectural elements dating from the same period. The apses of the cathedral, the bell tower and a part of the bishop's palace are all built on the foundations of an ancient temple.
In Roman times, the city flourished and it was also a favourite holiday destination for the aristocracy, hence the many elegant villas and homes. The town still attracts tourists today, because of the thermal baths located near the centre.
Ferentino's period of greatest splendour, however, was the Middle Ages, when the town was the seat of the papal legate. It remained the chief town of southern Lazio until the mid-16th century. The Romanesque church of Santa Maria Maggiore, built in the Cistercian Gothic style in the mid-12th century, is worthy of note. The sober façade features a large, central rose window, while inside it has a nave and two aisles in the Gothic style.