In this article, I seek to define the difficult legal phrase utroque iure caruerunt (“and they have been deprived of both laws”), which appears in capitulum XII of the Legatine Capitulary of 786 (a collection of canons promulgated ostensibly by a papal legation sent to England in order to address unspecified abuses), describing a punitive sanction for malefactors who have committed or conspired to commit the crime of regicide. I have been able to identify no parallel occurrence of this phrase in any culturally similar or temporally proximate documents, leaving me with little beyond the text itself to seek evidence for its precise meaning. Since it has been demonstrated recently that Alcuin — a native-born Anglo-Saxon and a Northumbrian — was intimately involved in drafting the Legatine Capitulary (if, indeed, he was not the sole author), and moreover, since this phrase appears in a text composed in the first instance for a Northumbrian audience, I argue that this phrase is deeply rooted in Anglo-Saxon legal precedents. I conclude that the phrase signifies that those guilty of regicide should be deprived of both secular and ecclesiastical law, that is, that they should be both outlawed and excommunicated. As such, this phrase represents the first reference to the legal sanction of outlawry in Anglo-Saxon law by more than a century. Additionally, this phrase would appear to take for granted the close cooperation between ecclesiastical and secular jurisprudence specifically to punish crime, a feature of Anglo-Saxon law likewise not formally described (according to current thought) until more than a century later. I finish by considering the implications of my argument for the history of Anglo-Saxon law, suggesting in particular that we must revise currently held opinions about the pace of its development, particularly in the Anglian North, where — due most likely to the loss of evidence resulting from the Viking invasions — very little primary-text evidence has survived.