The OPCK system of doctrine is the Reformed faith, also called Calvinism. Since the establishment of the Presbyterian Church and Calvin's doctrines continued to develop after his death, and a particular evolution of them was set forth by a 17th-century assembly of British theologians in the Westminster Standards (which include the Westminster Confession of Faith and the Westminster Larger Catechism|Larger and Westminster Shorter Catechism|Shorter Catechisms). The OPC holds to the Westminster Standards with the American revisions of 1788.