Parity in ecclesiastic judicial parlance, signifies the equality of rights of different religious denominations inn their relations to the state; those states. therefore, are parital which have granted equal rights to the several churches established in their domains. The principle of parity, totally unknown to Christian antiquity and the Middle Ages, has but gradually attained recognition since the Reformation. It was at first, and that only partially, acknowledged in the relations of the Lutheran estates to the German empire, by the Augsburg (religious) compact of 1555, which however excluded the Reformed (Calvinistic) Church; yet for the single territories the professed creed of the reigning prince was determinative. In the Peace of Westphalia (1648) this territorial principle was restricted or abolished; but the denominational character, in spite of the imperial statutes, continued in the single territories with manifold restrictions. The Netherlands, after their struggle for liberation, and Cromwell and the English commonwealth of the 17th century, were the first to pronounce and practice the principle of religious toleration (q.v.) at least of all evangelical sects; in Germany it was the great elector who carried out the parity of the Reformed with the Lutheran Church at the Westphalian peace. But only after the principle cujus reqio, ejus religio the maxim prevalent in the 15th and 16th centuries had yielded to the influence of the doctrine of universal human rights, the idea of the state parity for the different churches came to prevail, and is now incorporated in the constitutions of the European states. In Germany parity was formally declared only as late as the act of the Rheonish Confederation, by art. xvi; in 1806. In America it has been acknowledged since the establishment of the Union; in Pennsylvania it had been introduced by William Penn, who may properly be considered the founder of our parity idea. In the details, the position of the several religious corporations towards the state is regulated according to the constitution and law of the land;the peculiar motive idea is that every one of the generally recognized, religious communities shall enjoy equal rights and equal protection in the state; and in this aspect parity is only a part of universal freedom in religious matters. Parity asks no more than that the state deal equally with every religious denomination, but by no means that it permit every one to draw the full practical consequences, irrespective of the, communal life of the state. Thus, for instance, the reservation of the "placet" (q.v.) was not incompatible with parity.