The territories in question covered an area of 14,000 km2 (5,400 sq mi), having both geopolitical importance due to their proximity to the Spanish Road and a booming economy, fueled by refugees from the lands ravaged by the Eighty Years' War.
[1] The mentally ill duke Johann Wilhelm died on 25 March 1609, leaving no children, and the Emperor Rudolf II had claims to the duchies stemming from intermarriage but was unable to openly declare his intentions without compromising his perceived neutrality.
Leopold triumphantly entered Jülich but soon found himself besieged by an army three times his size, as fighting spread to Aachen and Düren.
Rudolf's initial decision to enfeoff the entire duchy to Christian II, Elector of Saxony was rejected by a number of moderate princes, leading to the postponement of negotiations until August.
Their fate was sealed as the Kingdom of France and the Dutch Republic finally intervened in support of the Protestants, aiming to antagonize Spain by putting further pressure on the Spanish Road.
The war severely depleted the coffers of all the involved parties, leading to increased taxes which in their turn triggered the 1612 Tyrol Peasant Revolt.
Occupiers Wolfgang Wilhelm, Count Palatine of Neuburg and Joachim Ernst, Margrave of Brandenburg-Ansbach took over the duchy by military might, without being able to secure official recognition.
The rebels assaulted the church and the college of the Jesuits, smashed the altars and images and held a mock mass dressed in priestly garments.
[4][5] Upon Rudolf's death, Emperor Matthias confirmed Saxony's rights to the fief, rekindling the dispute and the conversions of the Count Palatine and the Margrave to Calvinism and Catholicism respectively completely restructured their past alliances.
Another misunderstanding took place when Spain and Albert VII, Archduke of Austria interpreted the Dutch military buildup as a violation of the Twelve Years' Truce, mobilizing 13,300 infantry and 1,300 cavalry under Spanish general Ambrogio Spinola.
Fearing an attack, the town council requested the aid of the Elector of Brandenburg, who sent several hundred soldiers under General Georg von Pulitz to reinforce the local militia.
Spain gained a total of 62 towns including three Rhine crossings, namely Wesel, Orsoy and Rheinberg, significantly enhancing its position in north-west Europe.
The Dutch retained their garrisons at Jülich and Pfaffenmütze but were outflanked or isolated, putting them in an unfavourable position when the Twelve Years' Truce expired in April 1621.
Spain seized the opportunity to strengthen its hold on the Rhineland region by dispatching a 10,000 man army under Hendrik van den Bergh towards Jülich besieging it in September 1621.
[14] In June 1651, 3,800 Brandenburg troops invaded Berg, killing two civilians, bombarding Wolfgang Wilhelm's palace and seizing a herd of cows belonging to his wife.
Wolfgang Wilhelm employed the help of Charles IV, Duke of Lorraine, who launched a counter invasion of Mark with the intention of obtaining provisions for his army.