The Greek writer Ptolemy mentioned the Town of Fulfinum, which developed in the middle of the 1^st century. The discovery of a slab with carved text built into the basilica’s bell tower in 1974 also brought an answer to the question about the town’s location! Fulfinum (or its remains) can still be found in the Sepen Bay, in the area of Mirine, under ground, but also a few metres below the sea.

According to some sources, the largest early Christian basilica in the Mediterranean, dating back to the 5^th century, is also situated in the Sepen Bay near Omišalj. Excavations and research are still on-going in this area, and it is well known that the Benedictine Abbey of St. Nicholas that was later located on the site of the basilica, was mentioned in 1252, in a document written by Pope Innocent IV. As far as its surface area is concerned, this was the largest Benedictine Abbey.