Carlos, who declared his support for the ancient, pre-Bourbon privileges of the "fueros", received considerable support from the Basque country, Aragon, and Catalonia, which valued their ancient privileges from Madrid. The insurrection seemed, at first, a catastrophic failure for the Carlists, who were quickly driven out of most of Aragon and Catalonia, and forced to cling to the uplands of Navarre by the end of 1833. At this crucial moment, however, Carlos named the Basque Tomás de Zumalacárregui, a veteran guerrilla of the Peninsular War, to be his commander-in-chief. Within a matter of months, Zumalacárregui reversed the fortunes of the Carlist cause and drove government forces out of most of Navarre, and launched a campaign into Aragon. By 1835, what was once a band of defeated guerrillas in Navarre had turned into an army of 30,000 in control of all of Spain north of the Ebro River, with the exception of the fortified ports on the northern coast.