The Swiss Reformer Ulrich Zwingli developed his religious ideas in the town of Zurich, Switzerland, at a time that was parallel to but separate from the religious development of Luther:
What was wonderful to him and his generation was that they had before their eyes the original Greek, and Hebrew texts. The very words directly inspired by the Holy Spirit were there for them to read, and the printing press made possible an exactness unknown previously. It was in 1516 that this great treasure had been delivered into Zwingli’s hands, and early 1519 allows exactly the right length of time for assimilation and cogitation….
Zwingli must have brought with him to Zurich one of the best libraries possessed at the time by a simple secular priest, and his books he esteemed all his life. Many threads were now being drawn together in 1519-1520 – memories of rather barren university scholasticism with no desire on his part to return to Aristotle, Peter Lombard, Aquinas, Scotus and the rest, yet he knew them well and was therefore suitably equipped to meet his opponents in verbal-logical Latin discussions, each knowing that the other side was well trained in the formalities of logical thought….
Bold and even corrosive as some of [his] preaching was, it was already, as it always remained, basically and fundamentally Christ-centred. The Cross, and all that it meant, was never absent: the tidings were of eternal salvation. (G.R. Potter, “Zwingli”, Cambridge University Press, ©1976, pgs 64-65).
Zwingli is often a forgotten character in the Reformation, where Luther and Calvin are the best known among the Reformers. But Zwingli set the stage for later Reformers in Switzerland, including Heinrich Bullinger and John Calvin. McGrath places him in context:
The origins of the Reformed church lie with developments within the Swiss Confederation. Whereas the Lutheran Reformation had its origins primarily in an academic context, the Reformed church owed its origins more to a series of attempts to reform the morals and worship of the church (but not necessarily its doctrine) according to a more biblical pattern.
Although most of the early Reformed theologians – such as Huldrych Zwingli (1484–1531) – had an academic background, their reforming programs were not academic in nature. They were mainly concerned with reforming the practices (such as the worship) of the churches in the Swiss cities, such as Zurich, Berne, and Basle.
Whereas Luther was convinced that the doctrine of justification by faith was of central significance to his program of social and religious reform, the early Reformed thinkers had relatively little interest in doctrine, let alone this one specific doctrine. Their reforming program was institutional, social, and ethical, in many ways similar to the demands for reform emanating from the humanist movement. … for the moment it is important simply to note that all the major early Reformed theologians had links with the humanist movement which were not shared by Luther, who regarded it with some suspicion.
The consolidation of the Reformed church is generally thought to have begun with the stabilization of the Zurich reformation after Zwingli’s death (in battle, 1531) under his successor, Heinrich Bullinger (1504–75), and to have ended with the emergence of Geneva as its power base and John Calvin (1509–64) as its leading spokesman, in the 1550s.
McGrath, Alister E., “Reformation Thought: An Introduction” (pp. 7-8). Wiley. Kindle Edition.