sentences:  While not an original source "per se", the antiquity of the compiled list supports the assertion that Pehthelm was the first bishop at Whithorn, and contradicts later assertions (discussed below) that he was the second bishop.The modern editor of the book that it appears in reasons that it was written in the Kingdom of Mercia by a Northumbrian scribe.Later sources
  In his "Deeds of the Bishops of England" (1125), William of Malmesbury briefly mentions Pehthelm as the first bishop at Candida Casa, adding that he was a "disciple" of Aldhelm in "Westsaxonia", and saying that the diocese had later failed due to incursions by the Picts and Scots.