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. This is a repetition of information known from earlier sources, except that the assertion that Pehthelm was Aldhelm's disciple (or pupil) is William's own characterisation. In the Chronicon ex chronicis (1140), John of Worcester notes that Pehthelm of Candida Casa is one of the four bishops of Northumberland in 731, and that he died in 735 and was succeeded by Frithowald. This is a repetition of information from earlier sources. Conflicted sources The Chronicon ex chronicis (1140) also contains a list of the names of the Bishops of Whithorn located in "The Territory of the Picts", with Pehthelm listed as the second bishop, after Trumwine. Trumwine was consecrated as bishop of the Picts in 681, and his diocese was briefly based at Abercorn, just south of the Firth of Forth. However, this was abandoned after the Pictish victory over the Northumbrians at the Battle of Nechtansmere in 685. By the twelfth century when the Chronicon was written the compiler of the list seems to have assumed it as Trumwine's domain, as in the 12th century Galloway was commonly described as "Pictish" in northern English sources. Bede makes clear that Candida Casa was a new diocese and Pehthelm was its first bishop. In his Annals of Galloway, Ritson notes the error in the Chronicon and condemns the propagation of this mistake by late writers rather vigorously. Richard of Hexham, writing about 1141, provides yet another medieval chronicle largely repeating the accounts of Bede and the Anglo-Saxon Chronicle, and borrowing from the work of Symeon of Durham. However, he also says that he has heard that Acca of Hexham (c. 660 – c. 742) left his see at Hexham and had a role in the preparations for and founding of the episcopacy of Candida Casa. The suggestion is widely regarded as spurious, as