Ulrich Zwingli has been dubbed by many "the father of covenant theology."  His covenant theology was developed as a part of his defense of the doctrine of infant baptism over against the "radical reformers" of the Anabaptist tradition.  Though many of his actions associated with the controversy cannot be condoned, it nevertheless provided the impetus for him to formulate important aspects of the doctrine of the covenant that would remain a staple of Reformed theology well into the next two centuries.  Chief among these are the doctrine of the essential unity of the one, eternal covenant of grace.