In 1818 Pius VII merged the diocese of Gaeta with the very ancient see of Fondi.
Among its bishops of note were: Francesco Patrizio (1460), friend of Pius II, author of a work in nine books, De Regno et De Institutione Regis, dedicated to Alfonso, Duke of Calabria; and Tommaso de Vio, better known as the famous Thomas Cajetan, a Dominican theologian and Papal diplomat.