Why did Catalonia and Aragon oppose Bourbon rule during the War of the Spanish Succession?

During the War of the Spanish Succession, Catalonia and Aragon opposed the Bourbon dynasty primarily because they viewed the centralizing reforms of Philip V as an imposition of Castilian authority that threatened their local privileges, known as fueros.1

The Bourbon administration sought to create an efficient, centralized state to extract resources for the war effort, which directly conflicted with the autonomy of these regions. For the Catalans and Aragonese, the establishment of effective royal rule was seen as a violation of their traditional liberties. Furthermore, the Bourbon civil servants viewed these regional privileges with suspicion, believing they served as a cover for treasonable sympathies toward the Austrian and English invaders who supported the archduke Charles.1

As the conflict progressed, the resistance in Catalonia and Aragon became tied to their support for the archduke, leading to the eventual abolition of their fueros and the integration of these territories into a more unitary Spanish state under the Decree of Nueva Planta.12