However, repressive measures of the viceroy Francisco de Velasco and authoritarian decisions of the king (some of them contrary to Catalan legislation), as well as the economic policy and distrust to the French absolutism caused Catalonia to switch sides.

During the early part of the war, Barcelona, the capital of Catalonia, had fallen to the forces of Archduke Charles: his fleet had anchored in the port on 22 August 1705, landing troops which surrounded the city.

[3] By 25 July of that year, the city of Barcelona was surrounded by Bourbon forces under the command of Restaino Cantelmo-Stuart, Duke of Popoli, but attacks upon it were unfruitful due to the scarcity of artillery.

After a failed attempt to enter in the city on 30 August, the Bourbons finally triumphed on 11 September, when the assault which started at 4:30 in the morning was successful, as the wall fell in several places and the Conseller en cap and chief commander of the Coronela (the urban militia of Barcelona), Rafael Casanova, was wounded during the fight.

The talks were extended until the next day, due to the desires of Philip V to punish the population without any kind of agreement, but Berwick, fearing a prolonged struggle, formally accepted to respect the lives of Barcelonians.

The Catalan defeat represented the end of the Principality of Catalonia as a separate state, as its independent institutions and legislation were suppressed and replaced by Castilian ones in order to establish absolutism.