Page "Thirty Years' War" Paragraph 20

Tensions escalated further in 1609, with the War of the Jülich succession, which began when John William, Duke of Jülich-Cleves-Berg, the ruler of the strategically important United Duchies of Jülich-Cleves-Berg, died childless.

There were two rival claimants to the duchy.

The first was Duchess Anna of Prussia, daughter of Duke John William's eldest sister, Marie Eleonore of Cleves.

Anna was married to John Sigismund, Elector of Brandenburg.

The second was Wolfgang William, Count Palatine of Neuburg, who was the son of Duke John William's second eldest sister, Anna of Cleves.

Duchess Anna of Prussia claimed Jülich-Cleves-Berg as the heir to the senior line, while Wolfgang William, Count Palatine of Neuburg claimed Jülich-Cleves-Berg as Duke John William's eldest male heir.

Both claimants were Protestants.

In 1610, to prevent war between the rival claimants, the forces of Rudolf II, Holy Roman Emperor occupied Jülich-Cleves-Berg until the dispute was decided by the Aulic Council ( Reichshofrat ).

However, several Protestant princes feared the Emperor, a devout Catholic, intended to keep Jülich-Cleves-Berg for himself to prevent the United Duchies falling into Protestant hands.

Representatives of Henry IV of France and the Dutch Republic gathered forces to invade Jülich-Cleves-Berg, but these plans were cut short by the assassination of Henry IV.

Hoping to gain an advantage in the dispute, Wolfgang William converted to Catholicism ; John Sigismund, on the other hand, converted to Calvinism ( although Anna of Prussia stayed Lutheran ).

The dispute was settled in 1614 with the Treaty of Xanten, by which the United Duchies were dismantled: Jülich and Berg were awarded to Wolfgang William, while the John Sigismund gained Cleves, Mark, and Ravensberg.