The answer to the question posed by my title may surprise those coming at it as ‘Chaucerians’: in fact, texts other than the Tales appear in these manuscripts nearly half the time. While a number of manuscripts do contain only the Tales, some thirty-five of the eighty-three surviving manuscripts (counting Ox1 and Ox2 as one), or about 42%, contain texts other than the Canterbury Tales. Fifty-four manuscripts contain oncecomplete or near-complete copies of the Tales, while twenty-nine (again, counting Ox1 and Ox2 as one) either contain extracts or are too fragmentary to resolve the question of their original scope.
Among these ‘Canterbury Tales manuscripts’, aside from the Canterbury Tales proper, I count some 240 Middle English verse texts, 65 Middle English prose texts, 16 Latin prose texts, 10 Latin verse texts, and a single French verse text. While many of these occur only once or twice in Canterbury Tales manuscripts, we can get a sense of what comprised at least one version of the fifteenth century's ‘greatest hits’ by looking at the remaining texts that occur in three or more manuscripts. Of surviving manuscripts containing later Middle English verse, those containing the text of the Canterbury Tales number second only to those with The Prick of Conscience. While it is well-known that Lydgatian texts appear frequently with texts by Chaucer and are often attributed to Chaucer, the wide range of both secular and religious texts speak to the varying perspectives from which Chaucer's texts were read and received.
Two texts make five appearances in Canterbury Tales manuscripts: John Lydgate's Siege of Thebes (Ad1 Ch Cn En3 Ll1) and Chaucer's ‘Truth’ (Balade de Bon Conseyl: Ad4 Gg Ha3 Ph4 Pp[2]). The inclusion of the Siege of Thebes should not be too surprising, since Lydgate composed it as a Canterbury Tale, told by himself as the first homeward tale.
Five texts appear in four Canterbury Tales manuscripts: Chaucer's Parliament of Fowls (Gg Ha3 Pp[1] Tc3), Chaucer's ‘An ABC’ (Gg Hl2 Pp[1] Pp[2]), Benedict Burgh's ‘Cato Minor’ and ‘Cato Major’ (Ha3 Hl2 Hn Pp[1]), Lydgate's Churl and Bird (Ch Cn Hn Tc3), and extracts from Gower's Confessio Amantis (Dl Ee Ha3 To2).