The beautiful Chapel of St. Trinity in Rovinj, Croatia was built in the 12th century and is said to be the oldest building in Rovinj, Croatia. A small sign tells the name in three different languages (Croatian, Italian and English):
Sedmerokutna romanicka kapela
Sv. Trojstva
Cappella ettagonale romanica
della SS.ma Trinità
Hectagonal Romanic chapel of St.
Trinity
"The Chapel of St. Trinity
The Chapel of St. Trinity is the most important and best preserved Romanesque building in Rovinj and the whole of Istria. It is located on the Puddle Square near the bus station. It dates back from the 12th century, and is in the form of a heptagon whose exterior structure contains a circular area with seven niches and a dome. It contains all the characteristics of the transition of Romanesque art into the Gothic. A true gem of the local indigenous art represents a preserved transenna depicting Golgotha, with figures of Virgin Mary, Magdalene, St. John the Baptist, St. Peter and St. John. Today there are no services in the church; it is excellently preserved and converted into a gallery space. This church, which was once an isolated place, was at one point managed by a brotherhood who fought for the liberation of slaves."
Source: triprabbits.com/en/holy-trinity-chapel-rovinj-croatia-see-and-do-in-attractions/