Abstract In 1220 Queen Isabella, King John’s widow and mother to King Henry III, married the Poitevin lord, Hugh of Lusignan. The match generated tensions at the English court, which were partly resolved by a newly discovered truce of 1222, presented here. The existence of this document had been widely assumed but never proved. The document itself reveals the territorial deal brokered by Henry III: one of the earliest in a long series of written agreements between the Lusignans and the Plantagenets. More generally, it sheds light on thirteenth-century truce-making, marital diplomacy and Anglo-French politics.