However, the junta's power rested upon a basis too narrow for stability. Representing only the Santiago aristocracy, there was no certainty that its orders would be respected in the provinces, or that independent juntas would not be set up in other cities. To remedy this difficulty a national congress was summoned, but the junta allotted to Santiago almost as many members as to all the other municipalities together. The elections took place in April, 1811, and while they were going on the Spanish officer in command of a detachment at Santiago revolted. A member of the junta, José Carrera by name, an active and ambitious young man, who belonged to one of the most influential Creole families, distinguished himself by attacking and defeating the Spaniard with an improvised force of armed patriots. When congress met it voted many reforms; abolishing slavery, reorganising the judiciary, freeing commerce of vexatious restrictions, decreeing the payment of the clergy out of the public treasury instead of by tithes, and conferring on the elective bodies of the municipalities the right to elect their own city officers. However, divisions soon arose among the members. The representatives of the outside provinces bitterly complained of the unfairness of the apportionment; the radicals wished to reorganise everything, while the conservatives insisted on preserving many of the old institutions. The Santiago representatives, chosen from the landed aristocracy, were mostly conservative, while the members from the South were largely radical. Under the leadership of Doctor Rosas, the latter withdrew. The Santiago conservatives, left in undisputed control of congress, displaced the old junta, but Carrera and his two brothers had made themselves all powerful in the army by cleverly seizing its Spanish officers. He determined to ally himself with the radicals and assume supreme power. Marching to the hall of congress at the head of his troops, he compelled the selection of a new junta with himself as chief, and expelled the members upon whom he could not rely. Rosas had meanwhile established a radical junta at Concepcion, and Carrera offered to associate him in the government. Rosas declined, and the Santiago leader, now frankly a military dictator, advanced with an army to reduce the South to obedience. But the news that the Spanish party had gained the ascendancy in Valdivia and Chiloë intimidated him, and he made peace with Rosas, retiring to Santiago. His emissaries nevertheless continued to intrigue in Concepcion and finally stirred up a riot which resulted in Rosas' expulsion.