Prague. Abandoned by their confederates, who had been reconciled to the
Emperor, they formed a still closer alliance with France, which
increased her support with their growing necessities, at the same time
taking a more active, although secret share in the German war, until at
last, she threw off the mask altogether, and in her own name made an
unequivocal declaration of war against the Emperor.

To leave Sweden at full liberty to act against Austria, France commenced
her operations by liberating it from all fear of a Polish war. By means
of the Count d'Avaux, its minister, an agreement was concluded between
the two powers at Stummsdorf in Prussia, by which the truce was
prolonged for twenty-six years, though not without a great sacrifice on
the part of the Swedes, who ceded by a single stroke of the pen almost
the whole of Polish Prussia, the dear-bought conquest of Gustavus
Adolphus. The treaty of Beerwald was, with certain modifications, which
circumstances rendered necessary, renewed at different times at
Compiegne, and afterwards at Wismar and Hamburg. France had already
come to a rupture with Spain, in May, 1635, and the vigorous attack
which it made upon that power, deprived the Emperor of his most valuable
auxiliaries from the Netherlands. By supporting the Landgrave William
of Cassel, and Duke Bernard of Weimar, the Swedes were enabled to act
with more vigour upon the Elbe and the Danube, and a diversion upon the
Rhine compelled the Emperor to divide his force.

The war was now prosecuted with increasing activity. By the treaty of
Prague, the Emperor had lessened the number of his adversaries within
the Empire; though, at the same time, the zeal and activity of his
foreign enemies had been augmented by it. In Germany, his influence was
almost unlimited, for, with the exception of a few states, he had
rendered himself absolute master of the German body and its resources,