Complete agreement finally came about in 1577, after the death of both Melanchthon and Flacius, when a new generation of theologians resolved the doctrinal controversies on the basis of Scripture in the Formula of Concord of 1577. Although they decried the visible division of Christians on earth, orthodox Lutherans avoided ecumenical fellowship with other churches, believing that Christians should not, for example, join together for the Lord's Supper or exchange pastors if they do not completely agree about what the Bible teaches. In the 17th century, Georgius Calixtus began a rebellion against this practice, sparking the Syncretistic Controversy with Abraham Calovius as his main opponent. In the 18th century, there was some ecumenical interest between the Church of Sweden and the Church of England. John Robinson, Bishop of London, planned for a union of the English and Swedish churches in 1718. The plan failed because most Swedish bishops rejected the Calvinism of the Church of England, although Jesper Swedberg and Johannes Gezelius the younger, bishops of Skara, Sweden and Turku, Finland, were in favor. With the encouragement of Swedberg, church fellowship was established between Swedish Lutherans and Anglicans in the Middle Colonies. Over the course of the 1700s and the early 1800s, Swedish Lutherans were absorbed into Anglican churches, with the last original Swedish congregation completing merger into the Episcopal Church in 1846. In the 19th century, Samuel Simon Schmucker attempted to lead the Evangelical Lutheran General Synod of the United States toward unification with other American Protestants. His attempt to get the synod to reject the Augsburg Confession in favor of his compromising Definite Platform failed. Instead, it sparked a Neo-Lutheran revival, prompting many to form the General Council, including Charles Porterfield Krauth. Their alternative approach was "Lutheran pulpits for Lutheran ministers only and Lutheran altars...for Lutheran communicants only."
Question: Who were the two key figures involved in the Syncretistic Controversy?
Answer: Georgius Calixtus | Abraham Calovius