However, while differences over religion and Imperial authority were important factors in causing the war, some contemporary commentators suggest its scope and extent were driven by the contest for European dominance between Habsburg-ruled Spain and Austria, and the French House of Bourbon.

Although Imperial forces quickly suppressed the Bohemian Revolt, Frederick's participation expanded the fighting into the Palatinate, whose strategic importance drew in the Dutch Republic and Spain, then engaged in the Eighty Years' War.

[32] 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.

Losing control of these threatened the entire Habsburg state, while Bohemia was one of the most prosperous areas of the Empire and its electoral vote crucial to ensuring Ferdinand succeeded Matthias as Emperor.

Attempts by Maximilian and John George of Saxony to broker a negotiated solution ended when Matthias died in March 1619, since many believed the loss of his authority and influence had fatally damaged the Habsburgs.

Maximilian of Bavaria funded a combined Imperial-Catholic League army led by Count Tilly and Charles of Bucquoy, which pacified Upper and Lower Austria and occupied western Bohemia before marching on Prague.

Despite defeat in Bohemia, Frederick's allies included Georg Friedrich of Baden and 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.

[52] 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.

[58] In early 1626, Cardinal Richelieu, main architect of the alliance, faced a new Huguenot rebellion at home and in the March Treaty of Monzón, France withdrew from northern Italy, re-opening the Spanish Road.

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.

[74] Despite the devastation inflicted by Imperial soldiers, Saxony and Brandenburg had their own ambitions in Pomerania, which clashed with those of Gustavus; previous experience also showed inviting external powers into the Empire was easier than getting them to leave.

[87] A few days later, the German states and Ferdinand agreed to the Peace of Prague; in return for withdrawing the Edict of Restitution, the Heilbronn and Catholic Leagues were dissolved and replaced by a single Imperial army, although Saxony and Bavaria retained control of their own forces.

[100] After Bernard died in July 1639, his troops joined Banér's Swedish army on an ineffectual campaign along the Weser, the highlight being a surprise attack in January 1641 on the Imperial Diet in Regensburg.

[106] While Ferdinand accepted a military solution was no longer possible, by fighting on he hoped to prevent the Imperial Estates joining his peace negotiations with France and Sweden, thus preserving his authority by allowing him to represent the Empire as a whole.

[111] Soon after Rocroi, Ferdinand invited Sweden and France to attend peace talks in the Westphalian towns of Münster and Osnabrück,[112] but negotiations were delayed when Christian of Denmark blockaded Hamburg and increased toll payments in the Baltic.

[117] Deprived of Imperial support, John George of Saxony signed a six-month truce with Sweden in September, and in the March 1646 Treaty of Eulenberg agreed to remain neutral until the end of the war.

[122] Although the mutinies were quickly suppressed, Maximilian felt obliged to follow Werth's example and in September ordered Bronckhorst-Gronsfeld to combine the remnants of the Bavarian army with Imperial troops under von Holzappel.

While a relatively minor conflict, the struggle had a disproportionate impact on the Thirty Years War, since Pope Urban VIII viewed Habsburg expansion in Italy as a threat to the Papal States.

[132] Richelieu took advantage of the diversion of Imperial resources to fund a Swedish invasion of Germany, whose success forced the Spanish-Savoyard alliance to withdraw from Casale and sign the Treaty of Cherasco in April 1631.

[134] However, the anti-Habsburg alliance in northern Italy fell apart when first Charles of Mantua died in September 1637, then Victor Amadeus in October, whose death led to a struggle for control of the Savoyard state between his widow Christine of France and brothers, Thomas and Maurice.

[137] However, it exposed the weakness of Spanish rule in Italy and the alienation of the local elites from Madrid; in 1650, the governor of Milan wrote that as well as widespread dissatisfaction in the south, the only one of the Italian states that could be relied on was the Duchy of Parma.

[150][151] Key elements of the Peace were provisions confirming the autonomy of states within the Empire, including Ferdinand's acceptance of the supremacy of the Imperial Diet, and those seeking to prevent future religious conflict.

The political disintegration of Poland-Lithuania led to the 1655 to 1660 Second Northern War with Sweden, which also involved Denmark, Russia and Brandenburg, while two Swedish attempts to impose its control on the port of Bremen failed in 1654 and 1666.

[163] Although regular outbreaks of disease were common for decades prior to 1618, the conflict greatly accelerated their spread, due to the influx of soldiers from foreign countries, the shifting locations of battle fronts and displacement of rural populations into already crowded cities.

[166] Poor harvests throughout the 1630s and repeated plundering of the same areas led to widespread famine; contemporaries record people eating grass, or too weak to accept alms, while instances of cannibalism were common.

Even when adequate provisions could be gathered, the next problem was getting them to the troops; to ensure security of supply, commanders were forced to stay close to rivers, then the primary means of bulk transportation, and could not move too far from their main bases.

Attributed by religious authorities to divine retribution for sin, attempts to identify a supernatural cause led to a series of witch-hunts, beginning in Franconia in 1626 and quickly spreading to other parts of Germany.

[189] They began in the Bishopric of Würzburg, an area with a history of such events going back to 1616 and now re-ignited by Bishop von Ehrenberg, a devout Catholic eager to assert the church's authority in his territories.

[197] Bertolt Brecht used it as the backdrop for his 1939 anti-war play Mother Courage and Her Children, while its enduring cultural resonance is illustrated by the novel Tyll; written by Austro-German author Daniel Kehlmann and also set during the war, it was nominated for the 2020 Booker Prize.

This made it easier to levy national forces of significant size, loyal to their state and its leader; one lesson learned from Wallenstein and the Swedish invasion was the need for their own permanent armies, and Germany as a whole became a far more militarised society.