There is common consensus that the Norman cathedral was constructed on the site of an ancient Celtic church, but there is little consensus on the original church's age, importance or size.
Welsh tradition associates the church's founding with Lucius, the legendary King of the Britons and the first Christian convert in Britain.
This tradition attributes the church's founding to Saint Dyfan and Saint Fagan.

Further legends were popularised by pseudo-historical writings such as those of Geoffrey of Monmouth and Iolo Morgannwg.
These would include the re-establishment of a Christian community at Llandaff by Saint Dyfrig (Dubricius) and his successor Saint Teilo.
The most notable legends surrounding these two would state that Saint Dyfrig was made Archbishop by Saint Germanus of Auxerre while he travelled through Britain to oppose the Pelagian heresy, and linked both saints with King Arthur.

The Normans considered Dyfrig and Teilo as the cathedral's original founders and today, they are the modern Cathedral's patron saints, along with their successor Oudoceus.
The modern Bishop of Llandaff holds Saint Dyfrig to be the first bishop at Llandaff and the continuation of a Post-Roman church at the site is supported by secular and ecclesiastical writings, as well as by the remains of an ancient Celtic cross at the Bishop's Court's well.
There is common consensus that the Norman cathedral was constructed on the site of an ancient Celtic church, but there is little consensus on the original church's age, importance or size. Welsh tradition associates the church's founding with Lucius, the legendary King of the Britons and the first Christian convert in Britain. This tradition attributes the church's founding to Saint Dyfan and Saint Fagan.
Further legends were popularised by pseudo-historical writings such as those of Geoffrey of Monmouth and Iolo Morgannwg. These would include the re-establishment of a Christian community at Llandaff by Saint Dyfrig (Dubricius) and his successor Saint Teilo. The most notable legends surrounding these two would state that Saint Dyfrig was made Archbishop by Saint Germanus of Auxerre while he travelled through Britain to oppose the Pelagian heresy, and linked both saints with King Arthur.
The Normans considered Dyfrig and Teilo as the cathedral's original founders and today, they are the modern Cathedral's patron saints, along with their successor Oudoceus. The modern Bishop of Llandaff holds Saint Dyfrig to be the first bishop at Llandaff and the continuation of a Post-Roman church at the site is supported by secular and ecclesiastical writings, as well as by the remains of an ancient Celtic cross at the Bishop's Court's well.
Llandaff Cathedral