Catholicism has had a significant presence in the Cyclades, dating back to the early 13th century after the fall of Constantinople to the Franks in 1204 and the subsequent rule of a large part of the Byzantine Empire by the Franks.

Catholic Metropolis

Catholic Cathedral of the Presentation of the Lord. Constructed during the early years of Venetian rule in the 13th century, the Catholic Metropolis is the most important church in the castle area. Today, it stands as a five-aisled church with three domes. The remarkable marble reliefs on the floor depict the coats of arms of the dukes of Naxos. Notably, four coats of arms, including that of Markos Sanoudos, can be seen at the top of the central entrance. Inside the central nave, there is an altar adorned with wood carvings from 1774, as well as the impressive icon of Panagia Eleousa, believed to date back to the 11th or 12th century.

Catholic Archdiocese

Situated behind the Catholic Metropolis, the building of the Catholic Archdiocese of Naxos and the Metropolis of All the Aegean dates back to the 13th century. It underwent modifications until it acquired its present form in the 18th century. Initially serving as the seat of the Catholic bishopric of Naxos in 1207, it later became the Archbishopric of all the islands in 1522. It is the oldest Catholic archbishopric in the East and boasts an impressive interior. The Archdiocese houses an interesting collection that includes architectural elements, reliefs, folklore materials, engravings, icons, and ecclesiastical vessels, among others.

Chapel of Sanoudos

Also known as Kapela Kazatza (church-house), this chapel is believed to have been built by Marcos Sanoudos in the 13th or 14th century to accompany his tower. Traditionally, it served as the chapel for all the dukes of Naxos. Completed in 1680, the chapel is dedicated to the Immaculate Conception of the Virgin.

Saint Anthony of Padua

Saint Anthont is an elegant Catholic church located behind the Catholic Metropolis. The central altar is dominated by the icon of St. Anthony of Padua, which likely originated from France and made its way to Naxos. One of the church's most beautiful features is the pulpit adorned with intricate wooden carvings. The adjacent Capuchin monastery, active from 1628 to 1956, is housed in a building donated to the brotherhood by the Naxian nobleman Ioannis Anapliotis (also known as the Nafpliotis), who spent the last 30 years of his life with the Capuchins.