The arrival of the Saxonian army at Bohemia and the occupation of Prague and of the Duchy of Frýdlant changed the situation and career of the dismissed imperial commander Albrecht von Wallenstein fundamentally. These events made him to accept the position of the supreme commander again, despite of the fact, he was not interested in that any more.
He created great army for the jing Ferdinand III., he forced the Saxons out form the Bohemian Kingdom and he entered upon the campaign against the Swedish king Gustav II. Adolf, who was the most feared enemy of the Emperor.
The campaign finished by the dead of the king in the battle of Lützen.