Why was the Catholic League created in 1609?

The Catholic League was established in 1609 primarily as a defensive counter-alliance in response to the formation of the Protestant Union in 1608.123

The creation of the League was driven by several key factors:

• Protestant Mobilization: Following the "Donauwörth incident"—in which Bavarian troops occupied a city to restore Catholic worship—Protestant rulers formed the Protestant Union for mutual protection. This move alarmed Catholic leaders, who viewed it as a potential offensive against their faith.234
• The Cleves-Jülich Succession Crisis: The death of the Duke of Cleves-Jülich in 1609 created a power vacuum. When Protestant claimants occupied the territory with support from the Protestant Union, France, and England, Catholic princes felt compelled to organize a military response to prevent the expansion of Protestant influence in the region.34
• Religious Defense: Led by Maximilian I, Duke of Bavaria, the League was designed to stem the growth of Protestantism and protect the interests of the Roman Catholic Church within the Holy Roman Empire.13