Various, Encyclopaedia Britannica, 11th Edition…
“ After the departure of the Romans, the whole basin of the Teifi eventually fell into the power of Ceredig, son of Cunedda Wledig of North Wales; and the district, peopled with his subjects and nearly co-extensive with the existing shire, obtained the name of Ceredigion, later corrupted into Cardigan. During the 5th and 6th centuries Ceredigion was largely civilized by Celtic missionaries, notably by St David and St Padarn, the latter of whom founded a bishopric at Llanbadarn Fawr, which in the 8th century became merged in the see of St David’s. ”
