The Origins of the Thirty Years War? 29borders to fall under Habsburg control or influence, as seemingly threat-
ened by the involvement of Archduke Leopold, but it is less easy to
see what wider objectives he might have had. The increasingly accepted
view is that he was aiming at a swift intervention in overwhelming force,
both to secure the disputed duchies for the claimants and to prevent
further escalation. This would have been precisely in order to avoid the
outbreak of a major religious war which would have threatened French
internal stability, while at the same time gaining prestige for France as
an arbiter and peacemaker.^29 Even so it would have been a hazardous
undertaking.
Left in possession of the disputed duchies at the end of 1610, the
two claimants turned their efforts to outmanoeuvring each other in
an attempt to gain the whole inheritance. Little of note occurred for
the next three years, although in the course of 1613 each of them
changed their personal religion. Wolfgang Wilhelm of Pfalz-Neuburg
converted to Catholicism and married a Bavarian princess, while Elector
Johann Sigismund of Brandenburg switched from Lutheran to Calvinist,
although this was a less surprising move as many of his relations and
advisers had been Calvinist for some time. Nevertheless his conversion
met with opposition at home, including rioting in Berlin and distur-
bances in the Estates, so that he prudently agreed to tolerate both forms
of Protestant worship in the future.
There was a last flurry of activity in 1614, as each of the claimants
acquired the support of their new co-religionists. Spain backed Wolfgang
Wilhelm while the Dutch sided with Brandenburg, and in 1614 they
intervened militarily, the former taking the town of Wesel in the duchy
of Cleves while the latter occupied the fortress of Jülich. They had their
own interests principally in mind, as the territories were in a strategic
position bordering on the Dutch Republic and the Spanish Netherlands,
and troops of both powers had repeatedly occupied parts of them in the
past. Nevertheless it was a precarious situation, and one which endan-
gered the continuing twelve-year truce, but in the event neither side
wished to resume the war at that point. With the help of French and
English mediation a compromise was arranged between the claimants
in November 1614, the treaty of Xanten, whereby Wolfgang Wilhelm
gained Jülich and Berg, while Brandenburg acquired Cleves, Mark and
Ravensberg. Hence the former two territories regained a Catholic ruler,
while the latter group passed into the hands of a Calvinist, but religious
considerations were less relevant than the willingness of the dynastic
rivals to settle for what they could get, sharing the spoils rather than
risking destroying them by engaging in an all-out war.