The first Seminary of the Clergy was founded in 1572 and was located in the ancient Platea Magna, which today corresponds to Piazza Duomo.

After the earthquake of 1693 it was rebuilt in part on the ancient walls and in part on an area occupied by the ancient Bishopric; it was started by the architect Alonzo di Benedetto and continued by Francesco Battaglia. Over time it has undergone several modifications and today, the Palazzo dei Chierici, is home to offices of the Municipal Administration.

Descending the stairs to the right of the Palazzo dei Chierici you can see the Porta Carlo V, which is right in the middle of the Pescheria, the picturesque daily fruit and fish market. An inscription placed above the door commemorates the date, 1553: it was part of the walls erected to defend against pirate and enemy raids.