The author wishes to acknowledge in particular the article by C. Davidson Cragoe referenced at footnote 20 on p. 456 (‘Reading and rereading Gervase of Canterbury’, Journal of the British Archaeological Association cliv (2001)). In that article, Cragoe argued that Gervase wrote his Tractatus as ‘an attempt to put forward the monks' case for themselves, capable of creating the finest church in the land, suitable for housing both the pre-eminent English archbishop and the pre-eminent English martyr’ (pp. 50–1). The present piece takes and develops Cragoe's hypothesis about the motivation behind, and the date of, Gervase's Tractatus, and relies upon Cragoe's article for other information relating to that work. Readers following the line of argument presented here are encouraged to consult Cragoe's article as a complement.