The long list of conflicts between Ankara and Athens, from eastern Mediterranean maritime zones to Syrian refugees frozen to death at the Greek border, have a new addition: young DJs at a fourth-century Christian Orthodox site in northern Turkey.

On Wednesday, following a protest from Athens over the “desecration” of the UNESCO-listed Sumela Monastery, Turkey’s Tourism and Culture Ministry opened an inquiry into an electronic music concert that took place there at the end of January.

In the steep mountains of Turkey’s northern Black Sea region, Panagia Soumela Monastery — as it is called in Greek — dates to 386 AD. The majestic structure, located in the northern city of Trabzon, drives thousands of tourists from Greece every year, including those whose ancestors have lived in Turkey before the population exchange of 1923. They regard the visit as a “pilgrimage” to their ancient home.

President Recep Tayyip Erdogan, whose family hails from the nearby Black Sea city of Rize, has repeatedly referred to the monastery’s restoration as a symbol of Turkey’s commitment to protecting its non-Muslim heritage.