According to the Book of Llan Dav he was a disciple of Dyfrig and gave his name to Llangynfarch, which is St Kinmark, near Chepstow. Another Cynfarch has church dedications in N. Wales and at Llanfair Dyffryn, Clwyd there was once a sanctus Kynvarch represented in a stained-glass window. Feast: 8 September.
Baring-Gould and Fisher, ii. 241–2.