The remains of the still magnificent old Christian basilica, called Mira, built in the 5th century, rise on a flat plateau of the cove Sepen. It stands there as a reminder of the first indications of Christianity on the island of Krk. The layout of the church has the shape of the Latin cross, the symbol of Christianity. The remains of the cross confession (a symbolic tomb where saint relics used to be kept) are located within an inscribed apse, above which there was an altar. The narthex (vestibule), situated in the west, contained tombs, among which there was a sarcophagus. Along the basilica, towards the sea, there is a cloister enclosed by a thick wall with two high towers, only partially preserved. The original appearance of the church was entirely preserved so this structure is a valuable and rare “living” witness of its time.

A hundred meters to the west of the large old Christian basilica, there are the remains of a smaller church and a modest monastery complex. They emerged in the 9th century by reconstruction of the Roman thermae from the 1st – 2nd century.  The hypocaust of the thermae can still be seen today under the wooden bridge on the promenade along the sea.

The church with its dimensions is a modest edifice of a unique volume, with three apses enclosed within its flat back wall. On the southern side there is a memorial cella, with an apse also inscribed into the flat back wall. The remains of the monastery rooms were found to the west of the church.