Sant'Antioco di Bisarcio is located on an isolated volcanic hill. In medieval times this church was a cathedral, as diocese with seat in Bisarcium existed upto 1515. Today only scanty remains of the town still exist. Some foundations near the church were being excavated in 2014.

The elaborate facade, completed in 1174, seems "french" - and is very uneven. Left and right sides differ clearly. The left side must have been severely damaged once. Behind the window in the center is the bishop´s private chapel, a feature typical for older, carolingian churches. The bell tower seem to have crumbled quite a bit.