96 Wallenstein
militarily and politically significant, but also provided him with a valu-
able income from trade and tolls with which to finance further cam-
paigning. During 1626 he had landed an army in Prussia, ignoring the
neutrality and protests of his brother-in-law, the elector of Brandenburg,
to whom Prussia belonged, although it was a part of Poland and not of
the Empire. Nevertheless his presence there was a potential threat to
Pomerania, and hence to Germany, as well as to the Habsburg territory
of Silesia, presenting two possible directions in which a Swedish attack
might be launched in support of the emperor’s enemies. Gustavus’s
incursion was intended more to further his Polish campaign than to
position him for such an attack, but Wallenstein could not ignore the
risk, for if Sweden were to enter the war before Denmark could be driven
out of it the threat to the Imperialist position would be grave. Moreover
both countries were havens for Bohemian refugees, and indeed Thurn,
who had commanded the forces of the revolt, was serving as a field
marshal and third-in-command of the Danish army. These exiles were
waiting eagerly to join any advance into Habsburg territory, where
their first aim would be to recover their confiscated lands, Wallenstein’s
purchases foremost among them.
Despite his illnesses and frustrations Wallenstein prepared thor-
oughly for the campaign of 1627. Central to his planning was to ensure
that when he eventually confronted Christian he would have the
superior force at his disposal, while still having enough other troops
to deploy against threats elsewhere. Hence he set out to build his army
up into the largest early modern Europe had thus far seen, of the order
of 100,000 men in total.^28 His growing reputation also enabled him
to attract outstanding officers to strengthen his higher levels of com-
mand. Notable among them was Hans Georg Arnim, a Protestant and
a Brandenburger by birth, a soldier by profession and something of a
diplomat by temperament. He had already served ten years as a colonel
with Gustavus Adolphus, as well as briefly with the king of Poland and
even more briefly with Mansfeld, a progress which was not then unusual
for a career officer. Although he appeared an unlikely applicant to join
the Catholic Imperial army he quickly became not only a key officer but
also Wallenstein’s trusted confidant. Highly capable as well as highly
educated, and noted for his probity, piety and sobriety, he was far from
typical of the officer corps of the day, which may well explain his high
standing with Wallenstein. It was to prove a fateful relationship.
Wallenstein’s first concern was to reduce the risk of intervention by
Sweden, or at least to delay it. The most promising approach was to
keep Gustavus entangled in his Polish war, and to prevent him from