Scots and Swedish troops to Stralsund, commanded by Alexander Leslie who was also appointed governor. Von Arnim was forced to lift the siege on 4 August, but three weeks later, Christian suffered another defeat at Wolgast. He began negotiations with Wallenstein, who despite his recent victories was concerned by the prospect of Swedish intervention, and thus anxious to make peace. With Austrian resources stretched by the outbreak of the War of the Mantuan Succession, Wallenstein persuaded Ferdinand to agree to relatively lenient terms in the June 1629 Treaty of Lübeck. Christian retained his German possessions of Schleswig and Holstein, in return for relinquishing Bremen and Verden, and abandoning support for the German Protestants. While Denmark kept Schleswig and Holstein until 1864, this effectively ended its reign as the predominant Nordic state. Once again, the methods used to obtain victory explain why the war failed to end. Ferdinand paid Wallenstein by letting him confiscate estates, extort ransoms from towns, and allowing his men to plunder the lands they passed through, regardless of whether they belonged to allies or opponents. Anger at such tactics and his growing power came to a head in early 1628 when Ferdinand deposed the hereditary Duke of Mecklenburg, and appointed Wallenstein in his place. Although opposition to this act united all German princes regardless of religion, Maximilian of Bavaria was compromised by his acquisition of the Palatinate; while Protestants wanted Frederick restored and the position returned to that of 1618, the Catholic League argued only for pre-1627. Made overconfident by success, in March 1629 Ferdinand passed an Edict of Restitution, which required all lands taken from the Catholic church after 1555 to be returned. While technically legal, politically it was extremely unwise, since doing so would alter nearly every single state boundary in North and Central Germany, deny the existence of Calvinism and restore Catholicism in areas where it had not been a significant presence for nearly a century. Well aware none of the princes involved would agree, Ferdinand used the device of an Imperial edict, once again asserting his right to alter laws without consultation. This new assault on 'German liberties' ensured continuing opposition and undermined his previous success. In the Spanish Netherlands the balance of power had by now shifted in favour of the Dutch Republic. The financial predicament of the Spanish Crown had steadily worsened in the 1620s and the sensational success of the