Compurgation, also called wager of law, is a defence used primarily in medieval law

Law

Law is a system of rules and guidelines which are enforced through social institutions to govern behavior, wherever possible. It shapes politics, economics and society in numerous ways and serves as a social mediator of relations between people. Contract law regulates everything from buying a bus...

. A defendant could establish his innocence or nonliability by taking an oath and by getting a required number of persons, typically twelve, to swear they believed the defendant's oath.

Compurgation was found in early Germanic law

Early Germanic law

Several Latin law codes of the Germanic peoples written in the Early Middle Ages survive, dating to between the 5th and 9th centuries...

, in Welsh law

Welsh law

Welsh law was the system of law practised in Wales before the 16th century. According to tradition it was first codified by Hywel Dda during the period between 942 and 950 when he was king of most of Wales; as such it is usually called Cyfraith Hywel, the Law of Hywel, in Welsh...

, and in the English ecclesiastical courts until the 17th century. In common law

Common law

Common law is law developed by judges through decisions of courts and similar tribunals rather than through legislative statutes or executive branch action...

 it was substantially abolished as a defence in felonies by the Constitutions of Clarendon

Constitutions of Clarendon

The Constitutions of Clarendon were a set of legislative procedures passed by Henry II of England in 1164. The Constitutions were composed of 16 articles and represent an attempt to restrict ecclesiastical privileges and curb the power of the Church courts and the extent of Papal authority in England...

in 1164. The defence was still permitted in civil actions for debt and vestiges of it survived in England until its final abolition in 1833.