 On 30 September 1986, Pope John Paul II ordered that the dioceses of Veroli, Frosinone, and Ferentino be merged into one diocese with one bishop, with the Latin title "Dioecesis Frusinatensis-Verulana-Ferentina".The seat of the diocese was to be in Frosinone, whose cathedral was to serve as the cathedral of the merged dioceses.The cathedrals in Veroli and Ferentino were to become co-cathedrals, and the cathedral Chapters were each to be a "Capitulum Concathedralis".