Political security is often viewed as a necessary precondition for rulers to develop property-protecting legal institutions. I argue that because these institutions can build political support and generate revenue, domestically insecure rulers may also invest in them. I test this argument using newly collected 12th-century data on the operation of the nascent English common law system. Leveraging the 1192 shipwreck and subsequent kidnap of Richard I as an exogenous shock to domestic political security, I find that the catastrophe appears to have prompted the English Royal Court's short-term deployment to raise political support in areas vulnerable to rebellion. I present suggestive evidence that this effect in vulnerable areas persisted into the medium-term, and appears to have expanded to the rest of the country. Drawing on this and other evidence of changes in Royal Court funding, activity, and organization between 1184 and 1203, I argue that the shock may have helped to bring about a permanent increase in the Court's capacity and accessibility. These findings are relevant to studies of the common law and the political economy of legal institutions generally.