Spanish American wars of independence important change in strategy after three United Provinces campaigns had been defeated in Upper Peru. San Martín's army became the nucleus of the Army of the Andes, which received crucial political and material support in 1816 when Juan Martín de Pueyrredón became Supreme Director of the United Provinces. In January 1817, San Martín was finally ready to advance against the royalists in Chile. Ignoring an injunction from the congress of the Río de la Plata not to move against Chile, San Martín together with General Bernardo O'Higgins Riquelme, later Supreme Director of Chile, led the Army over the Andes in
Army of the North a victory at Utarango but was later defeated on 12 February by the San Juan river. Rondeau received an order to retreat to Tucumán. The army, almost beaten, marched for nine months going through Potosí and Humahuaca until reaching Tucumán. On 7 August 1816 at Trancas, Rondeau was replaced again by Manuel Belgrano. Martín Miguel de Güemes was named commander of the northern border. Belgrano moved the army to the citadel built by San Martín in the city of Tucumán. There he attempted to rebuild the morale, and materials, in search for a new action in Upper Peru, combining with