Marsala Cathedral

Marsala Cathedral (Italian - duomo di San Tommaso di Canterbury) is the largest church in the town of Marsala, Sicily, and the Diocese of Mazara del Vallo. Its facade faces onto piazza della Repubblica and the nearby via Giuseppe Garibaldi.

It is dedicated to the Anglo-Norman saint Thomas Becket, whose cult was introduced to Sicily via its close relations with England under William I and William II – the latter even married Henry II of England's daughter Joan, who also supported Thomas' cult despite Henry's part in triggering his death. From the first half of the 2nd century to the 9th century it was the seat of the Diocese of Lilybaeum.

Remains survive of a basilica cathedral which survived from the first half of the 2nd century until the 9th century. That diocese was suppressed during the Arab era on the island.

As recorded by Al Idrisi, Marsala was commercially eclipsed by Mazara by the time of the Norman conquest of the island and so – on the re-establishment of a diocese covering the area in the 11th century – its seat was placed in Mazara not Marsala.

It is now the seat of the archpriest and foranial vicariate of Marsala, the parish of San Tommaso Becket and (since 1966) of the titular diocese of Dioecesis Lilybaetana, The third of these entitles it to the title of cathedral.