In October 1529, Philip I, Landgrave of Hesse, convoked an assembly of German and Swiss theologians at the Marburg Colloquy, to establish doctrinal unity in the emerging Protestant states.

Although competing forms of Christianity emerged early and persisted into the 5th century, there was broad doctrinal unity within the mainstream churches.

"Unlike all Protestant churches in America, the Roman Catholic church depended for its identity upon keeping doctrinal and administrative unity with a European-based authority."

In a formal statement, they declared their commitment to "doctrinal unity in functional diversity", placing an emphasis on strict doctrinal uniformity.

Thus, the creation of the Assemblies of God marked an official end of Pentecostal doctrinal unity.

Lutheran theology entered a period of doctrinal unity with the adoption of the Book of Concord and preserved it through the work of theologians such as Chemnitz and Gerhard.

Martin wrote this book to analyse the sudden and rapid decline of the Roman Catholic Church in its ecclesiastical organization and doctrinal unity since the Second Vatican Council (1962-1965).

In discussions from 2 to 7 January 1539, Bucer and Witzel agreed to defer controversial points of doctrine, but Melanchthon withdrew, feeling that doctrinal unity was a prerequisite of a reform plan.

Martin Bucer is chiefly remembered for his promotion of doctrinal unity, or ecumenism, and his lifelong struggle to create an inclusive church.

Beginning around 1184, following the crusade against the Cathar heresy, various institutions, broadly referred to as the Inquisition, were established with the aim of suppressing heresy and securing religious and doctrinal unity within Christianity through conversion and prosecution.