But the Emperor could not look on with indifference, while Denmark was
sacrificed to Sweden, and the latter strengthened by so great an
acquisition. Notwithstanding great difficulties lay in the way of so
long a march through desolated provinces, he did not hesitate to
despatch an army into Holstein under Count Gallas, who, after
Piccolomini's retirement, had resumed the supreme command of the troops.
Gallas accordingly appeared in the duchy, took Keil, and hoped, by
forming a junction with the Danes, to be able to shut up the Swedish
army in Jutland. Meantime, the Hessians, and the Swedish General
Koenigsmark, were kept in check by Hatzfeldt, and the Archbishop of
Bremen, the son of Christian IV.; and afterwards the Swedes drawn into
Saxony by an attack upon Meissen. But Torstensohn, with his augmented
army, penetrated through the unoccupied pass betwixt Schleswig and
Stapelholm, met Gallas, and drove him along the whole course of the
Elbe, as far as Bernburg, where the Imperialists took up an entrenched
position. Torstensohn passed the Saal, and by posting himself in the
rear of the enemy, cut off their communication with Saxony and Bohemia.
Scarcity and famine began now to destroy them in great numbers, and
forced them to retreat to Magdeburg, where, however, they were not much
better off. The cavalry, which endeavoured to escape into Silesia, was
overtaken and routed by Torstensohn, near Juterbock; the rest of the
army, after a vain attempt to fight its way through the Swedish lines,
was almost wholly destroyed near Magdeburg. From this expedition,
Gallas brought back only a few thousand men of all his formidable force,
and the reputation of being a consummate master in the art of ruining an
army. The King of Denmark, after this unsuccessful effort to relieve
him, sued for peace, which he obtained at Bremsebor in the year 1645,
under very unfavourable conditions.

Torstensohn rapidly followed up his victory; and while Axel Lilienstern,