Not merely the Austrians and the German Catholic princes were in this combination, but also the Muscovites or Russians, and, most unnatural of all, the Danes, with countenance even from the more distant Dutch.

Nay, the prudent Elector of Brandenburg, hitherto the ally of the Swede, was drawn off from that alliance.

This was done by a treaty, dated Nov.

10, 1656, by which the Polish King, John Casimir, yielded to the Elector the full sovereignty of Ducal Prussia or East Prussia, till then held by the Elector only by a tenure of homage to the Polish Crown.

All being ready, the Danish King, Frederick III., gave the signal by declaring war against Sweden and invading part of the Swedish territories.