What caused Bolivar leads a surprise attack in 1819

In 1819, the War of Independence in Northern South America was locked in a stalemate. Venezuela was exhausted from a decade of war, and patriot and royalist warlords had fought each other to a standstill. Simón Bolívar, the dashing Liberator, conceived of a brilliant yet seemingly suicidal plan: he would take his 2,000 man army, cross the mighty Andes, and hit the Spanish where they were least expecting it: in neighboring New Granada (Colombia), where a small Spanish army held the region unopposed.

His epic crossing of the frozen Andes would prove to be the most genius of his many daring actions during the war.