 Those preferring the Roman tonsure considered the Celtic custom extremely unorthodox, and associated it with the form of tonsure worn by the heresiarch Simon Magus.This association appears in a 672 letter from Saint Aldhelm to King Geraint of Dumnonia, but it may have been circulating since the Synod of Whitby.The tonsure is also mentioned in a passage, probably of the 7th century but attributed wrongly to Gildas