These depict narrative scenes such as the Nativity, and their sophistication suggests the artists were from England or Normandy.
At the west end of the chapel is a beautifully-carved sarcophagus that may be the tomb of Cormac himself, or maybe his brother and predecessor, Tadhg (d.1124).
The sarcophagus probably originally stood in the 12th-century cathedral, which no longer survives.
The castle was accessed on the second floor from the passage in the nave walls.
The most attractive elements are the transepts (c.1270), with triple lancet windows.
The north portal has a gabled porch, indicating it was the main entrance before the cathedral was built up against the north side of the chapel.
The chapel's interior contains the oldest and most important Romanesque wall paintings in Ireland.