On the one hand Vienna lay almost within his grasp, for Wallenstein was now too far north to interpose between him and the capital.

On the other hand, should the Elector of Saxony join the Imperialists, his position after the capture of Vienna would be perilous in the extreme.

The emperor would probably leave his capital before he arrived there, and the conquest would, therefore, be a barren one.

Gustavus reluctantly determined to abandon his plan, and to march to the assistance of Saxony..