Here it is necessary to observe, that the two Dukes of Mecklenburg having been dispossessed of most of their dominions by the tyranny of the Emperor Ferdinand, and being in danger of losing the rest, earnestly solicited the King of Sweden to come to their assistance; and that prince, as he was related to the house of Mecklenburg, and especially as he was willing to lay hold of any opportunity to break with the emperor, against whom he had laid up an implacable prejudice, was very ready and forward to come to their assistance.

The reasons of his quarrel with the emperor were grounded upon the Imperialists concerning themselves in the war of Poland, where the emperor had sent 8000 foot and 2000 horse to join the Polish army against the king, and had thereby given some check to his arms in that war.

In pursuance, therefore, of his resolution to quarrel with the emperor, but more particularly at the instances of the princes above-named, his Swedish Majesty had landed the year before at Stralsund with about 12,000 men, and having joined with some forces which he had left in Polish Prussia, all which did not make 30,000 men, he began a war with the emperor, the greatest in event, filled with the most famous battles, sieges, and extraordinary actions, including its wonderful success and happy conclusion, of any war ever maintained in the world.

The King of Sweden had already taken Stettin, Stralsund, Rostock, Wismar, and all the strong places on the Baltic, and began to spread himself in Germany.  He had made a league with the French, as I observed in my story of Saxony; he had now made a treaty with the Duke of Brandenburg, and, in short, began to be terrible to the empire.

In this conjuncture the emperor called the General Diet of the empire to be held at Ratisbon, where, as was pretended, all sides were to treat of peace and to join forces to beat the Swedes out of the empire.  Here the emperor, by a most exquisite management, brought the affairs of the Diet to a conclusion, exceedingly to his own advantage, and to the farther oppression of the Protestants; and, in particular, in that the war against the King of Sweden was to be carried on in such manner as that the whole burden and charge would lie on the Protestants themselves, and they be made the instruments to oppose their best friends.  Other matters also ended equally to their disadvantage, as the methods resolved on to recover the Church lands, and to prevent the education of the Protestant clergy; and what remained was referred to another General Diet to be held at Frankfort-au-Main in August 1631.

I won’t pretend to say the other Protestant princes of Germany had never made any overtures to the King of Sweden to come to their assistance, but ’tis plain they had entered into no league with him; that appears from the difficulties which retarded the fixing of the treaties afterward, both with the Dukes of Brandenburg and Saxony, which unhappily occasioned the ruin of Magdeburg.