Published online by Cambridge University Press: 05 June 2012
In 1633 the European conflict that had begun in 1619 was entering its fifteenth year. After the savagely fought battle of Lützen in November 1632, which had claimed the life of Gustavus Adolphus of Sweden but had failed to undermine Swedish military power in the Empire, the following campaign proved a lacklustre affair. Neither the imperial army under Albrecht Wallenstein nor the Swedish–German army wanted to risk another major encounter. The imperial army ended the 1633 campaign in winter quarters on the territories of its Habsburg overlord, Emperor Ferdinand II. Early in January 1634, forty-seven senior officers, each the colonel-proprietor of at least one regiment, assembled at Pilsen, south-west of Prague, to discuss orders from the court at Vienna. The most significant instruction was to decamp into quarters in adjoining German territories, tantamount to fighting a winter campaign against the Swedish troops presently occupying these areas. Following the repudiation of the court directives, dismissed as operationally impractical, the assembled officers each signed a document in which they subscribed to an oath of unconditional obedience to Wallenstein.
At the time, and in the debates that have persisted ever since about Wallenstein's ‘treason’, the significance of this oath has been linked to the fact that Wallenstein had created the largest mercenary army ever seen in Europe. In early 1634 it had an effective strength of around 45,000, and at its peak in 1629 it had numbered over 100,000 soldiers on paper.