[1] It lies off the Bulgarian Black Sea Coast near Sozopol, a town with rich history and a popular tourist place, and is separated by a strait several hundred metres long from the small neighbouring St. Peter Island.

Next to the Thracian sanctuary, the locals built a temple of Apollo featuring a bronze statue by Calamis standing 13.2 metres (43 ft) in height, making it easy to see from the city.

After the conversion to Christianity, a monastical complex was built in the 5th-6th century on top of the ruins of the old Roman temple, including the Basilica of the Mother of God.

Archaeological research was carried out after 1985 for a couple of years, so today the remains of two churches, a royal residence, a library, part of the fortified wall with the gate and several monastic cells can be seen.

Two small islets or large rocks also existed to the east of St. Peter, known by the names of Milos and Gata; they were last described by Russian war correspondents in the 1820s.