This is without doubt the oldest church in Latisana. It was first mentioned in 1368. In the 18th century the Cathedral of St. John the Baptist underwent radical renovation, with the addition of Baroque elements to the facade. A few relics remain of the ancient church, probably in late-Romanesque style, including the whole frame of a rose window and its central keystone. The rose window elements are now displayed on the northern side of the church.