Just here also another element of contention for the rigid Lutherans was introduced. Calvin appeared as a king of medi ation between the Lutherans and Zwinglians; and he proposed by modifying the opinions of both parties to effect a more perfect union: but instead of his efforts being acceptable, the rigid Lutherans accused all who in the least degree fa vored the union of being Crypto-Calvinists; i.e., secret Calvin ists. By thus adding an epithet the prejudice was increased against any effort toward conciliation; and besides, a bitter controversy was opened between the Lutherans and Calvinists.