The roots of the wars of independence are to be found in the attempts made by Spain after 1765 to re-establish imperial control over its American colonies (see spanish empire). This was resented by the Creoles (colonial descendants of Spanish settlers), whose political authority, economic prosperity, and sense of national identity were threatened. Creoles in Spanish America achieved de facto economic independence, and with the abdication of Ferdinand VII (1808), political independence. In 1811 the first declarations of independence were made. Initially the movements were hampered by a counter-revolutionary drive by Spanish royalists. In 1816 Simón Bolívar returned to Venezuela from exile and united with José Antonio Páez and the Ilaneros (plainsmen) of the interior. With the assistance of British mercenaries Bolívar crossed the Andes and won the battle of Boyaca, and proclaimed the United States of Colombia (1819). The victories of Carabobo (1821) and Pichincha (1822) brought Venezuela and Ecuador into the Colombian Federation. Bolívar then linked up with the independence movement in the south under the leadership of San Martín, who had crossed the Andes from the United Provinces of La Plata (Argentina) and won the battles of Chabuco (1817) and Maipo (1818) and liberated Chile. Both movements now closed in on the bastion of the Spanish empire, Peru. The battles of Junin and Ayacucho (1824) were the final victories in the liberation of the continent.