German Reformer (1534-1583) and principal author of the Heidelberg Catechism (1563). Born Zacharias Beer at Breslau in Silesia (the German Latinization of Beer is Ursinus, little bear); trained at the University of Wittenberg (1550-1557) under Melanchthon and the other Wittenberg theologians; traveled extensively in 1557-1558 visiting Reformed centers (Worms, Strasbourg, Basel, Lausanne, Geneva, Lyon, Paris, Orléans), studying under Calvin at Geneva and Vermigli at Zurich. Returned to Breslau as schoolmaster (1558-1560); resigned over doctrinal controversy with strict Lutherans; recruited by Elector Frederick III of the Palatinate to teach at Heidelberg (1561). Ursinus served at Heidelberg from 1561 until 1577 (after Frederick III's death and the Lutheran reaction), then at the new Reformed Academy at Neustadt (1578-1583). Ursinus's principal contribution is the Heidelberg Catechism (1563), composed at the request of Elector Frederick III and accepted by the Synod of Heidelberg in 1563; the Catechism became one of the great Reformed-confessional documents, adopted across the Reformed world, particularly central to Dutch and German Reformed identity (it remains a confessional standard in the Reformed Church in America, the Christian Reformed Church, the Protestant Reformed Churches, the United Reformed Churches, and many other Reformed denominations). Ursinus also produced extensive theological lectures and commentary on the Heidelberg Catechism (his Commentary on the Heidelberg Catechism remains in print and use). The patriarchal-Reformed reader values Ursinus as the principal author of the most widely used Reformed catechism in history.