Please answer a question about the following article about Valencia:

Faced with this loss of business, Valencia suffered a severe economic crisis. This manifested early in 1519–1523 when the artisan guilds known as the Germanies revolted against the government of the Habsburg king Charles I in Valencia, now part of the Crown of Aragon, with most of the fighting done in 1521. The revolt was an anti-monarchist, anti-feudal autonomist movement inspired by the Italian republics, and a social revolt against the nobility who had fled the city before an epidemic of plague in 1519. It also bore a strong anti-Islamic aspect, as rebels rioted against Aragon's population of mudéjars and imposed forced conversions to Christianity.

Whose government did the guilds rebel against?
Charles I