Not knowing Bolivar's numbers, Barreiro, the Spanish commander, dared not attack, and the Liberator thus obtained a much-needed opportunity to rest his men and gather horses for his dismounted cavalry. As soon as he got his army in hand he outmanoeuvred Barreiro and by a rapid march captured the city of Tunja, where he found a good store of arms and material. This movement also placed the patriot army between the Spaniards and Bogota. Barreiro, seeing himself cut off from his base, made a desperate dash for the capital, but Bolivar knew the enemy's route and took up a position directly across his path on the right bank of the small river Boyaca. Though the patriots were only slightly superior in numbers, the Spaniards had to attack at a disadvantage, and fled completely defeated after losing a hundred men. Practically their whole force was dispersed or made prisoners. Small as were the numbers engaged and easily as it was won, Boyaca was the most important battle fought in northern Spanish America. Central New Granada, the wealthiest and most populous part of the country, fell into Bolivar's hands without a further blow. Its revenues relieved his financial difficulties and among its sturdy inhabitants he recruited a new army. Morillo, now isolated in Venezuela, must expect an attack from the llaneros, reinforced by the Granadan mountaineers. [Illustration: ROAD NEAR MACUTO.] During the Liberator's absence from Venezuela he had been branded as a traitor for abandoning his country without the authorisation of congress, and Marino made commander-in-chief. But the news of Boyaca fell like a thunderbolt among the disaffected, and his return in December quelled them utterly. No opposition was made when he announced that Venezuela and New Granada were united into a single republic, the United States of Colombia, with himself as president and military dictator. The year 1820 passed without any decisive campaign. Bolivar occupied himself principally in recruiting and refitting his armies. Twelve hundred Irish mercenaries arrived and were incorporated with an army which was sent by sea to threaten the Spaniards in Cartagena, and co-operate with the New Granadans on the lower Magdalena. A strong division of Venezuelans was sent against Quito. Paez with the main army of the Apure was, however, repulsed in an advance into Barinas. In spite of this success Morillo could only lie inactive south of Caracas. His forces were not numerous enough both to retake New Granada and to hold northern Venezuela. But word came that Ferdinand was preparing an army of twenty thousand men which would shortly sail from Cadiz for America, and with this reinforcement the marshal believed he could destroy all the patriot armies. The revolution which broke out in Spain in 1820 against Ferdinand's absolute government overturned his hopes. The expedition never sailed, and the new liberal government showed itself disposed to make terms with the revolted colonies.