In dogmatic theology, the event or process by which a person is made or declared to be righteous in the sight of God. The Latin justificare, from which the English word derives, etymologically implies the meaning ‘to make righteous’ ( justum facere), and this interpretation remained unchallenged until the Reformation. It was then argued that in the NT the equivalent Greek word (διΚαίωσις) and its cognates reflect Hebrew usage and are to be understood as legal metaphors signifying ‘vindication’ or ‘declaring [someone] to be righteous’. In classical Protestant theology, ‘justification’ was interpreted as God ‘declaring a person to be righteous’, and it was distinguished from sanctification, in which a person is ‘made righteous’. In both Lutheranism and Calvinism, justification is seen as an act of God, effected without human co-operation; according to the RC Church it requires a person's co-operation. A further difference concerns the formal cause of justification, which Protestants held to be the imputed righteousness of Christ, and the Council of Trent defined as the inherent or imparted righteousness of Christ.