This is the Chapel of the Eternal Fire in the Outskirts of Βίζιμα. It is where you will find the Αιδεσιμότατου during the day. At night, he can be found next door, in his house.
During the quest Dead Hand of the Past, Γκέραλτ gains entry to the Chapel and the crumbling sarcophagus in its cellar, and thus meets the King of the Wild Hunt and Leo, one last time.