[Sidenote: § 4. Opposite views as to what measures are needed.] That there was much to be done in this direction was openly acknowledged by almost all who had been concerned in the imperialist successes. Maximilian and the League held that it was above all things necessary to restrain the excesses of Wallenstein and his soldiers. Wallenstein held that it was above all things necessary to restrain the excessive demands of Maximilian and the clergy. Ferdinand, the man in whose hands fortune had placed the decision of the great question, probably stood alone in thinking that it was possible to satisfy both the soldiers and the priests without weakening his hold on the Empire. The first act of Ferdinand after the signature of the treaty was to invest Wallenstein formally with the Duchy of Mecklenburg. Offence was thus given to those who believed that the rights of territorial sovereignty had been unduly invaded, and who were jealous of the right claimed by the Emperor to supersede by his own authority a prince of the Empire in favour of a successful soldier. [Sidenote: § 5. Ill treatment of the Protestants.] On the other side offence was given still more widely to those who wished to maintain the rights of Protestantism. Without wishing to enter upon a general persecution, Ferdinand was resolved to allow no rights against his church to those who could not conclusively prove to his own satisfaction that those rights were under the guarantee of unassailable law. He had begun in his own hereditary dominions. It is true that in Bohemia and Austria no tortures were inflicted, no martyrs suffered either at the stake or on the scaffold. But it was found that the stern, relentless pressure of daily annoyance was sufficient for the purpose of producing at least external conformity. By 1627 the desired result had been obtained, and Protestantism existed only as a proscribed religion. Then came the turn of the Palatinate. For a time there had been no open persecution. In 1625 Maximilian had written to the governor of Heidelberg not to let any opportunity slip, if he could find an excuse for turning out a Protestant minister from his parish and replacing him by a Catholic priest. In February, 1628, the Jesuits were able to report that they had made 400 converts in Heidelberg itself, and 1,200 in the neighbouring country districts. Then came a further change. In March an agreement was drawn up between Maximilian and Ferdinand. The Emperor received back Upper Austria, and made over to the Elector of Bavaria, in its stead, the Upper Palatinate and that part of the Lower Palatinate which lies on the right bank of the Rhine. Maximilian held that by this transfer he had acquired the full rights of a territorial prince, and that amongst these rights was that of disposing of the religion of his new subjects. In June all noblemen residing in the country were told that they must either change their religion within two months or go into exile.