This edition refers to manuscript groups o a b cd ungrouped. The relationships between these groups are summarized in this stemma (to be published in Forthcoming), which sets out the relationships, as we have determined them, for the c. sixty full copies of the Tales:

In our analysis these relationships are stable across all sixty witnesses across the whole length of the Tales. There are exceptions: notably, Ch moves away from the o group for the Cook's Tale, El moves away from o in the first half of the Wife of Bath's Prologue, and manuscripts move irregularly between the o, ungrouped and cd groups. Compare Robinson 2026, p. 26 for the assertion that the world is a messy place, and accordingly stemmata are messy things. However, the broad consistency with which this stemma appears to hold across the whole Tales persuades us that there is a single textual history for the whole text. This runs against Dempster's assertion, based on her reading of Manly and Rickert, that each part of the Tales has a separate textual history, some twenty-five histories in all, with each separate history dependent on the existence of part-exemplars distributed before Chaucer's death. This view requires the existence of over two hundred part-exemplars, not one of which have survived. Our single stemma for the whole Tales makes our task as editors far easier. We do not aim at strict editing by recension, which would require us to hypothesize that every extant manuscripts must descend from separate copies below the ancestor ('hypearchtype'). Robinson's Anglia article argues that in a textual tradition of any size, strict recension is likely impossible, a conclusion which follows also from the editors' "Manuscripts with Few Significant Introduced Variants" Ecdotica article (2018.) Like Ralf Plate, we describe our editing as "stemmatically informed".
The five groups into which our stemma divides the manuscripts and pre-1500 print texts of the tales are as follows:

Among all the manuscripts of the Tales, three stand out for the excellence of their text and for their closeness not just in readings but also in fine details of spelling. Two of the three, El and Hg, have been long regarded by scholars as key to the tradition. We agree with this assessment and argue that their excellence derives from both manuscripts being direct copies from the o materials made by a single scribe known as "Scribe B" (Parkes and Doyle 1978). Scribe B appears to have been specially close to Chaucer (thus Mooney on Adam Pynkhurst; cf. Warner 2018). Ch has been long known to share many good readings with Hg and El. Our work has confirmed that this closeness extends to precise detail of wording and spelling, with analysis of the spelling of all three manuscripts showing that they are so close that it appears that Ch is a copy of a third manuscript, alongside El and Hg, also written by Scribe B (Forthcoming and 2025). Accordingly we regard Ch as deserving the same regard among editors as has been traditionally given to El Hg. This figure summarizes the relationship between Ch El Hg and o:
