The lines of descent for St. Afan of Buellt:
The name of the cantref of Buellt, Builth in English, derives from ‘bu’ and ‘gellt’ respectively meaning ‘ox’ and ‘pasture’. It occupied the northern portion of Brycheiniog and abuts onto Ceredigion. Afan’s grandfather, Tegid Foel who was the husband of Ceridwen, would have been a near contemporary of Ceredig ap Cunedda Wledig.
The church of Llanafan Fawr is dedicated to the saint as is that at Llanfechan. At the former is an inscription that reads:
HIC IACET SANCTUS AVANUS EPISCOPUS
but it is late, dating from the 13th/14th c. He also founded Llanafan Trawsgoed in Ceredigion.
His supposed death at the hands of Danes may be a conflation with the 10th c. Jeuan who was said to be bishop for one day.
Geraldus Cambrensis tells us:
“But here it is proper to mention what happened during the reign of king Henry the First to the lord of the castle of Radnor, in the adjoining territory of Builth, who had entered the church of Saint Avan (which is called in the British language Llan Avan), and, without sufficient caution or reverence, had passed the night there with his hounds. Arising early in the morning, according to the custom of hunters, he found his hounds mad, and himself struck blind.”
The text goes on to tell of his death in battle at Jerusalem.
 Westwood, J.O., 1879, 72.
 Jones, T., 1909, Vol. 1, 226.
 Rhys, E., 1908, 14.