The variant endings of Partonopeus de Blois are analysed in the light of an anti-Plantagenet subtext established in the Trojan genealogy of the hero in the Prologue. One subgroup of manuscripts contains interpolations into the ending which are designed to flatter the English King and counteract negative presentation of the English elsewhere in the text. These are accompanied by a series of subtle criticisms of the French, which are found in all the extant versions except manuscript A. This suggests that A, with its consistently developed anti-Plantagenet subtext, represents the nearest approximation to the original version of the romance, and not a later, idiosyncratic redaction as is usually suggested. The other endings are shown to represent the work of redactors who sought to neutralise A's hostile undertones. The Continuation, the final stage in the evolution of the romance, derives from this politically neutral type of ending. Partonopeus is generally dated relative to Florimont (1188) which draws obviously upon it; since it can be demonstrated that Florimont borrows from the Partonopeus Continuation, the earliest form of Partonopeus must substantially predate Florimont. A dating for the original of around 1170 is proposed; this is supported by other historical allusions in the text.