In the midst of the fighting which followed the overthrow of Santa Cruz, a liberal Constitution was proclaimed which attempted to take from the executive his preponderance in the government. Negro slavery was abolished and the movement was altogether in the direction of democracy and against the property-holding classes. In 1840 General Ballivian overcame all his rivals and gained supreme power. In the following year the dictator of Peru, taking advantage of the continual disputes over questions of transit through Peruvian territory, and thinking that in Bolivia's enfeebled condition she would not be able to resist incorporation, led a large army over the border and occupied the province of La Paz. But the Bolivians rallied around Ballivian and defeated the Peruvians in the battle of Yngavi near the end of 1841, a victory which definitely assured the independence of Bolivia. Ballivian had risen to power by brute military force and crushed out the feeble attempt at popular government made after the fall of Santa Cruz. Despotic, irritable, and ambitious, he had not the wide knowledge or administrative capacity of Santa Cruz, and he gave the country a much worse government. The pride of the turbulent half-breeds was roused by the victory over the Peruvians, and conspiracies and insurrections occurred more frequently. Ballivian ordered the liberal Constitution of 1839 to be repealed and the preponderance of the executive in the governmental system was restored by the Constitution of 1843. He ruled until 1848, but the partisans of Santa Cruz grew bolder and bolder. In spite of the president's efforts to surround himself with officials of talent and intelligence, the power of the government decreased. The irrational and artificial boundaries given to Bolivia by Bolivar continued to involve her in disputes with Peru, and in 1847 the imposition of practically prohibitive duties nearly brought on war. Ballivian assembled an army, but Castilla, the Peruvian president, found means to foment an insurrection, and the Bolivian president was soon engaged in a desperate conflict with the very men whom he had expected to lead against the foreign enemy. Successful at first in his operations, one mutiny was suppressed only to be followed by others more formidable, and he finally gave it up in disgust and retired to exile.