Thus attempts to bring about a General Council failed repeatedly. The nearest approach to reconciliation was achieved when a conference was arranged at Ratisbon (1541) at which there were papal as well as Lutheran representatives and it seemed as if common ground of agreement was in course of emerging. But Luther himself held aloof; Paul III. would not ratify the concessions that Contarini and others were willing to make. The Conference ended in failure; and Charles--always embarrassed in his dealings with the Protestants by his need of their support against threatening Turkish aggression--was obliged, a good deal against his private inclinations, to reaffirm the Nuremberg toleration. The result was a renewal of negotiations between Pope and Emperor for the calling of a General Council; whereof the outcome was that in May 1542 the Pope summoned the famous Council of Trent which did not conclude its sittings till twenty years later. Although the Council was formally called for the end of the year, it did not succeed in holding a working Session till 1546; after the spring of 1547 it was transferred to Bologna; nor did it get to work again (once more at Trent) till 1551. The fundamental point however is that, by its constitution, the Lutheran controversy was prejudged and the Lutheran party effectively excluded. It was not a Council representing Christendom; it stood for the Church of Rome seeking internal reformation for itself and arrogating Catholicity to itself. Hence arose the custom of using the terms Catholic and Protestant as party labels for those within and without the "orthodox" pale, in spite of the objection more particularly of the Anglican body to its implied exclusion from the "Catholic" Church and inclusion in the same category with the Lutheran and Calvinistic bodies. The historian cannot admit that Rome has a right to monopolise the title of Catholic; but during the period when Europe was practically divided politically into two religious camps, it is difficult to avoid using the current labels though their adoption is in some degree misleading. [Sidenote: 1548 Death of Luther] With the convocation of the Council of Trent, such hope as there had been for a reunion of Christendom was practically terminated. Its first working sessions in 1546 were contemporaneous with the death of the man who had led the revolt against Rome. But if Martin Luther had been a great cleaving force, in Germany itself his influence had been consistently exerted for national unity. To him more than to any other man it was due that Germany had not as yet been plunged into a civil war. He was hardly gone, when the forces of discord broke loose. [Sidenote: 1546-49 Charles and the Protestant League]