This is the largest and most elegant church inside the castle, which stands out at its westernmost end. The view from its yard over the sea goes all the way to Milos, Kimolos and Sifnos. It was built in the early 18th century and the costs were borne by Georgios Stais, a notable from Crete. In 1930 they found a valuable manuscript with important information on the disaster caused to Folegandros in October 1715 by the Ottomans.