Editing Thirty Years' War (section)

===Palatinate Campaign===
By abandoning Frederick, the German princes had hoped to restrict the dispute to Bohemia, but this was thwarted by Maximilian's dynastic ambitions. In the October 1619 [[Treaty of Munich (1619)|Treaty of Munich]], Ferdinand transferred the Palatinate's electoral vote to Bavaria, and allowed Maximilian to annex the [[Upper Palatinate]].{{Sfn|Stutler|2014|pp=37–38}} Many Protestants had supported Ferdinand because in principle they opposed the deposition of a legally elected ruler, and now objected to Frederick's removal on the same grounds. For Catholics, it presented an opportunity to regain lands and properties lost since 1555, a combination which destabilised large parts of the Empire.{{Sfn|Wedgwood|1938|p=117}}

[[File:Joachim von Sandrart - Maximilian I, Elector of Bavaria.jpg|thumb|left|upright=0.9|[[Maximilian I, Elector of Bavaria]] whose seizure of the Palatinate expanded the war]]

At the same time, the Spanish were drawn into the conflict due to the strategic importance of the Spanish Road for their war in the Netherlands, and its proximity to the Palatinate. When an army led by [[Gonzalo Fernández de Córdoba (1585–1635)|Córdoba]] occupied the [[Lower Palatinate]] in October 1619, James I responded to this attack on his son-in-law. English naval forces were sent to threaten Spanish possessions in the Americas and the [[Mediterranean]], while James announced he would declare war if Spanish troops were not withdrawn by spring 1621. These actions were primarily designed to placate his opponents in [[Parliament of England|Parliament]], who considered his pro-Spanish policy a betrayal of the Protestant cause.{{Sfn|Zaller|1974|pp=147–148}} Spanish chief minister [[Gaspar de Guzmán, Count-Duke of Olivares|Olivares]] correctly interpreted them as an invitation to open negotiations, and in return for an Anglo-Spanish alliance offered to restore Frederick to his Rhineland possessions.{{Sfn|Zaller|1974|pp=152–154}}

Since Frederick's demand for full restitution of his lands and titles was incompatible with the Treaty of Munich, hopes of a negotiated peace quickly evaporated. Despite defeat in Bohemia, Frederick's allies included [[George Frederick, Margrave of Baden-Durlach|Georg Friedrich of Baden]] and [[Christian the Younger of Brunswick|Christian of Brunswick]], while the Dutch provided him with military support after the Eighty Years' War restarted in April 1621 and his father-in-law James funded an army of mercenaries under Mansfeld. However, their failure to co-ordinate effectively led to a series of defeats by Spanish and Catholic League forces, including [[Battle of Wimpfen|Wimpfen]] in May 1622 and [[Battle of Höchst|Höchst]] in June. By November 1622, Spanish and Imperial troops controlled most of the Palatinate, apart from [[Siege of Frankenthal|Frankenthal]], which was held by a small English garrison under Sir [[Horace Vere]]. The remnants of Mansfeld's army took refuge in the Dutch Republic, as did Frederick, who spent most of his time in [[The Hague]] until his death in November 1632.{{Sfn|Spielvogel|2017|p=447}}

At a meeting of the Imperial Diet in February 1623, Ferdinand forced through provisions transferring Frederick's titles, lands, and electoral vote to Maximilian. He did so with support from the Catholic League, despite strong opposition from Protestant members, as well as the Spanish. The Palatinate was clearly lost; in March, James instructed Vere to surrender Frankenthal, while Tilly's victory over Christian of Brunswick at [[Battle of Stadtlohn|Stadtlohn]] in August completed military operations.{{Sfn|Pursell|2003|pp=182–185}} However, Spanish and Dutch involvement in the campaign was a significant step in internationalising the war, while Frederick's removal meant other Protestant princes began discussing armed resistance to preserve their own rights and territories.{{Sfn|Wedgwood|1938|pp=162–164}}