Protestant princes of the Empire were all Lutherans, and they merely thought of securing their own interests. Calvinism therefore had no rights whatever in the Empire, and had still to win its recognition from the law. [Sidenote: =2. The secularised lands.=] Secondly, it had been laid down by the peace that the Church should no longer have any rights over Church property lying within the territories of Lutheran princes, which had been secularised by them or applied by them to Lutheran purposes, before 1552; but differences had since arisen between the two parties as to the bearing of this provision upon lands secularised subsequently to 1552. It was argued by the Catholics, that the very fact that lands secularised before 1552 were expressly exempted from all the claims of the Church, clearly implied that lands secularised after 1552 were not subject to that exemption, and had therefore been taken from the Church illegally and ought to be at once restored. The Lutherans, on the other hand, maintained that the treaty intended to lay down a general rule, which was to apply to all lands secularised under similar circumstances, and the date only referred to the convention of Passau, which led to the religious peace, and was not meant to create two different classes of secularised lands. Following out this somewhat broad construction of the peace, large quantities of Church land had been secularised since 1552 by Lutheran and even by Calvinist princes, and used by them as a very convenient endowment for younger sons and other relations. [Sidenote: =3. The Ecclesiastical Reservation.=] A further difficulty arose with regard to what was called the Ecclesiastical Reservation. It frequently happened, during the earlier years of the Reformation, that a bishop or abbot, who was a territorial prince in right of his bishopric or abbacy,--of which there were a great number in Germany--became a Lutheran. In order to preserve the rights of the Church in such a case, it was provided by the peace of Augsburg, that a bishop or abbot who became a Lutheran should at once vacate his dignity. But the Protestants maintained that this Ecclesiastical Reservation, as it was called, was only intended to apply to cases where a bishop or abbot, who had been elected by a Catholic Chapter as a Catholic, became a Protestant, and did not affect those cases where a Chapter which had itself become Protestant elected a Protestant to be their bishop or abbot. In virtue of this contention, eight of the great bishoprics of north Germany and many abbacies throughout the country became practically secularised. The Protestant bishop or abbot made no pretence to ecclesiastical position or functions. He was merely a territorial prince who enjoyed the title of bishop, or sometimes administrator, instead of that of duke or landgrave, but his right to his title and his lands had never been admitted by the imperial courts or the Diet.