Partially surviving Life of Asaph probably dating to the thirteenth century. The original manuscript was lost and only the beginning of the Life has survived in transcription.

The Life describes the coming of Kentigern to Wales, initially to St Davids, and the establishment of Kentigern's monastery at Llanelwy (St Asaph). This incurs the indignation of Maelgwn, who was struck blind and sought forgiveness from Kentigern. Having completed the foundation of the church, Kentigern is called back to Glasgow, and the text from this point is lost, and does not tell us, as promised in the prologue, why the church is dedicated to Asaph and not to Kentigern.

Copied from the lost Red Book of Asaph, the best preserved transcription is found in Peniarth 231, produced around 1620 by Robert Vaughan.