The growth of clerical power and corruption, which led to papalism and made the Reformation necessary, had been a traditional subject in works of Lutheran historiography from the mid-sixteenth century onward. The common, orthodox view was that the decline had set in gradually, some centuries after the age of early Christianity, and that it culminated in the investiture contest of the eleventh century. The relationship between the church and the Christian emperors of late antiquity, however, had been exemplary, and Luther's Reformation had returned church-state relations in Protestant lands to this pure state of the age of Constantine and Theodosius the Great. Thomasius expressed strong doubts about this conventional interpretation and questioned whether the Reformation had actually succeeded in restoring the relationship between prince and church to its proper balance. Although he praised Luther's achievements in general, he believed Lutheranism had not been purged of all the faults that had affected the church in the centuries before. In particular, modern orthodox Lutheranism continued to grant the clergy excessive influence on secular affairs and therefore was only another variant of historical “papalism.” Thomasius also argued that the relationship between prince and church in late antiquity was not as uncorrupt as his orthodox opponents liked to suggest: papalism had already taken hold in the supposed golden age of the church's history under the early Christian emperors; it was the result of a corruption of faith that had begun even earlier, in the immediate post-apostolic era, and paradoxically was only made worse by the establishment of Christianity as the Roman Empire's state religion.

THOMASIUS's HISTORY OF THE EARLY CHURCH

Thomasius's pessimistic view of the early Christian emperors seems to have formed sometime in the early 1690s, at the same time as the change in his notion of religious belief, to which it is closely related. In his Rechtmäßige Erörterung of 1689, for example, his defense of the marriage of the Lutheran Maurice William of Sachsen-Zeitz with a Calvinist princess, Thomasius had still regarded the state of church government under Constantine as exemplary.