English: The Cathedral is the largest of the seven churches in Glendalough. It was built in several phases from the 10th through the early 13th century. Large mica schist stones, which form the foundation up to the height of the west doorway, were re-used from an earlier smaller church. The earliest part is the nave with antae for supporting the wooden roof. The chancel, sacristy, and north door were added in the late 12th and early 13th centuries.