Editing Thirty Years' War (section)

==Background: 1556 to 1618==
[[File:Map Thirty Years War-en.svg|left|thumb|upright=1.2|Map of the Thirty Years' War]]

Disputes occasionally resulted in full-scale conflict like the 1583 to 1588 [[Cologne War]], caused when its [[Gebhard Truchsess von Waldburg|ruler]] converted to Calvinism. More common were events such as the 1606 "Battle of the Flags" in Donauwörth, when riots broke out after the Lutheran majority blocked a Catholic religious procession. [[Rudolf II, Holy Roman Emperor|Emperor Rudolf]] approved intervention by the Catholic [[Maximilian I, Elector of Bavaria|Maximilian of Bavaria]]. In return, he was allowed to annex the town, and as agreed at Augsburg, the official religion changed from Lutheran to Catholic.{{Sfn|Wilson|2009|p=222}}

When the Imperial Diet opened in February 1608, both Lutherans and Calvinists sought re-confirmation of the Augsburg settlement. In return, the Habsburg heir [[Ferdinand II, Holy Roman Emperor|Archduke Ferdinand]] required the immediate restoration of any property taken from the Catholic Church since 1555, rather than the previous practice whereby each case was assessed separately. By threatening all Protestants, his demand paralysed the diet, and removed the perception of imperial neutrality.{{Sfn|Wilson|2009|p=224}}

Loss of faith in central authority meant towns and rulers began strengthening their fortifications and armies; outside travellers often commented on the growing militarisation of Germany in this period.{{Sfn|Parker|1997|p=11}} In 1608, [[Frederick IV, Elector Palatine]] formed the [[Protestant Union]], and Maximilian responded by setting up the [[Catholic League (German)|Catholic League]] in July 1609. Both were created to support the dynastic ambitions of their leaders, but combined with the 1609 to 1614 [[War of the Jülich Succession]], the result was to increase tensions throughout the empire.{{Sfn|Wedgwood|1938|pp=47–49}} Some historians who see the war as primarily a European conflict argue Jülich marks its beginning, with Spain and Austria backing the Catholic candidate, France and the [[Dutch Republic]] the Protestant.{{Sfn|Wilson|2008|p=557}}

[[File:CaminoEspañol.svg|thumb|right|upright=0.8|The [[Spanish Road]] <br /> '''Purple''': [[Habsburg Spain|Spanish]] dependencies <br /> '''Green''': Ruled by [[Habsburg monarchy|Austria]] <br /> '''Brown''': Ruled by Spain]]

External powers became involved in what was an internal German dispute due to the imminent expiry of the 1609 [[Twelve Years' Truce]], which suspended the [[Eighty Years' War]] between Spain and the Dutch Republic. Before restarting hostilities, [[Ambrosio Spinola]], commander in the Spanish Netherlands, needed to secure the [[Spanish Road]], an overland route connecting Habsburg possessions in Italy to [[Flanders]]. This allowed him to move troops and supplies by road, rather than sea where the Dutch navy was dominant; by 1618, the only part not controlled by Spain ran through the [[Electoral Palatinate]].{{Sfn|Wedgwood|1938|p=50}}

Since [[Matthias, Holy Roman Emperor|Emperor Matthias]] had no surviving children, in [[Oñate treaty|July 1617]] [[Philip III of Spain]] agreed to support [[Ferdinand II, Holy Roman Emperor|Ferdinand II]]'s election as king of Bohemia and Hungary. In return, Ferdinand made concessions to Spain in northern Italy and Alsace, and agreed to support their offensive against the Dutch. Doing so required his election as emperor, which was not guaranteed; Maximilian of Bavaria, who opposed the increase of Spanish influence in an area he considered his own, tried to create a coalition with Saxony and the Palatinate to support his candidacy.{{Sfn|Wedgwood|1938|pp=63–65}}

Another option was [[Frederick V, Elector Palatine]], a Calvinist who succeeded his father in 1610, and in 1613 married [[Elizabeth of Bohemia|Elizabeth Stuart]], daughter of [[James VI and I|James I of England]]. Four of the electors were Catholic, and three were Protestant; if this balance changed, it would potentially result in the election of a Protestant emperor. When Ferdinand became king of Bohemia in 1617, he also gained control of its electoral vote; however, his conservative Catholicism made him unpopular with the predominantly Protestant nobility, who were also concerned about the erosion of their rights. These factors combined to bring about the [[Bohemian Revolt]] in May 1618.{{Sfn|Wilson|2009|pp=271–274}}