The question of man's co-operation in his conversion gave rise to what was known as the /Synergist/ controversy. Luther had laid it down as a first principle that man contributed nothing to the work of his own conversion, but though Melanchthon agreed with this view in the beginning, he was disposed at a later period to attribute some activity to the human will, at least in the sense that it must struggle against its own weakness. This view was strengthened and developed by John Pfeffinger, a professor at Leipzig, who taught publicly the necessity of man's co-operation (1550), and published a treatise in defence of this position (1555). Pfeffinger's doctrine aroused the opposition of Amsdorf, Flacius, and the other leaders of the orthodox Lutheran party. Leipzig and Wittenberg joined hands to support the doctrine of co-operation, while the majority of the professors at Jena took the opposite side. One of the latter however, Strigel, supported Pfeffinger, and a public disputation was held at Gotha under the presidency of Duke John Frederick. The Lutheran party demanded the punishment of Strigel and his supporters so vigorously that the Duke was obliged to arrest them, but, annoyed by the attempt of the Lutherans to set up a religious dictatorship to the detriment of the supremacy of the civil ruler, he established a consistory composed of lawyers and officials whose duty it was to superintend the religious teaching in his territory. The anti-Synergists, having protested against this measure as an infringement of the rights of the spiritual authority, were expelled, and Jena entered into line with Wittenberg and Leipzig for the defence of Synergism. With the change of rulers came once more a change of doctrine. The princes, alarmed by the violence of the controversy, assembled a conference at Alternburg in 1568 which lasted four months without arriving at any agreement. On the accession of the Elector August the leading opponents of the Synergists, including a large number of the superintendents and preachers, were deprived of their offices.