On 15 November 1379, the new bishop, the Sicilian Matteo de Castiello, arrived in Nardò to a decidedly mixed reception.

His instructions were to make the monastery of S. Maria his cathedral and residence, and he therefore removed Abbot Guglielmo from governance over the territory of Nardò.

Bishop Matteo was expelled in 1401 and the diocese of the Avignon Obedience suppressed, following a change in allegiance of the Kingdom of Naples after the death of Urban VI.

A very great earthquake struck the area of Nardò on 5 December 1456, severely damaging the cathedral and causing the bell tower to collapse.

[8] In 1647, during the rebellions against Spanish rule in the Kingdom of Naples, the Count of Conversano captured Nardò and executed four of the Canons of the cathedral Chapter.

After wide consultations among all affected parties, Pope John Paul II issued a decree on 20 October 1980, elevating Lecce to the status of metropolitan see.

[14] On 18 February 1984, the Vatican and the Italian State signed a new and revised concordat, which was accompanied in the next year by enabling legislation.

According to the agreement, the practice of having one bishop govern two separate dioceses at the same time, aeque personaliter, was abolished.