Nestled in between a house and a student dorm in Koper's old town, the round sandstone building looks unassuming. In fact, it is believed to be the oldest buildings in the city. And now it has been completely renovated.

Known as the Koper Rotunda or Rotunda of the Assumption of the Virgin Mary, the building is believed to have been erected in the 11th century, though no precise records of its origin exist.

There are however written church records showing that it had been used as a baptistery prior to 1213, when a baptistery was built in nearby Izola.

Ground penetrating radar surveys conducted prior to the renovation also showed remains of a baptism pool that may have been built as early as the 5th or 6th century, according to Mojca Marijana Kovač of the National Institute for the Protection of Cultural and Historic Heritage.

Renovation started in 2022 and was completed just in time for celebrations this June of 1500 years since the appointment of the first bishop of Koper.

The works included removing a wooden cupola that had been added in the early 20th century and replacing roof tiles, renovation of the exterior facade, which is bare sandstone, and restoration of the interior.

The building is now home to paintings of saints made by the Italian artist Paolo Orlando, along with a 6th century altar plate found in the Koper Cathedral several years ago. The Koper Diocese also plans to use it for lectures and other events.