His Zwinglian view of the Eucharist disturbed his relations with his Catholic colleagues.
With regard to the relations between the Church and the civil power, Calvin was opposed to the Zwinglian theory whereby all ecclesiastical power was handed over to the state.
To his translation (1530) of a Latin Chronicle and Description of Turkey, by a Transylvanian captive, which had been prefaced by Luther, he added an appendix holding up the Turks as in many respects an example to Christians, and presenting in lieu of the restrictions of Lutheran, Zwinglian and Anabaptist sects, the vision of an invisible spiritual church, universal in its scope.
In his Christology he departed from the Lutheran and Zwinglian doctrine of the two natures by insisting on what he called the Vergotterung des Fleisches Christi, the deification or the glorification of the flesh of Christ.
In theology he followed Zwingli, and at the sacramentarian conferences of Heidelberg (1560) and Maulbronn (1564) he advocated by voice and pen the Zwinglian doctrine of the Lord's Supper, replying (1565) to the counter arguments of the Lutheran Johann Marbach, of Strassburg.