The remains of the Abbey can be visited
Sweti Iwan Abbey

The monastery ruin of Sweti Iwan is on the island of the same name off the Bulgarian Black Sea coast, near the town of Sosopol.
History+
As early as the late 5th century, a first monastery was established on the island. On the site where an Apollo statue once stood, the monastery basilica “Holy Mother of God” was built after 330 AD. In the Middle Ages, the monastery was rebuilt by Bulgarian tsars in the style of the Preslav School and was directly subordinate to the respective rulers. Between the 10th and 14th centuries, it was expanded several times, including a second monastery church dedicated to John the Baptist in 1263.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Original uploader was Mrs Robinson at bg.wikipedia / CC BY 2.5 via Wikimedia Commons
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 42.4369, 27.6920