sentences:  The church is a Grade I listed building as of 19 August 1955.The Mathern estate was traditionally given to the Bishops of Llandaff by King Meurig.It is known that, by 1333, Mathern was one of three medieval palaces belonging to Llandaff (the others being at Bishton and at Llandaff itself); and, after Owain Glyndŵr's rebellion in the early 15th century, it was the only one kept habitable.