After six years of peaceful government President Castilla was succeeded by President Echenique, whose administration lasted from 1851 to 1855, when he was deposed and President Castilla was reëlected. During his second term, this indefatigable statesman continued to devote his efforts to the improvement of the public service. Especial attention was given to the construction and discipline of the prisons. The foundations of the present penitentiary of Lima were laid in accordance with plans prepared and submitted by Dr. Mariano Paz Soldan, who had the work in charge. When, in 1862, the reins of government were passed to his successor, Grand Marshal Don Miguel San Román, President Castilla retired from office with everything to his credit that a patriot who has rendered good service to his country may claim. Three years later he became president of the Senate, at seventy years of age. By the terms of the constitution of 1860, the presidential period, which formerly lasted for six years, was reduced to four, the president not being permitted henceforth to succeed himself by reëlection for a second term. President San Román, son of the martyred patriot of Umachiri, lived only a few months after his election, and was succeeded by Vice-President Pezet, during whose administration a conflict arose with Spain, with dire consequences to the prestige of the president. The Chincha Islands were seized by a Spanish fleet on the pretext of guaranteeing certain unjust claims, and President Pezet, who found himself unable to offer resistance, was obliged to make a settlement with Spain which was so unfair to Peru that it called forth vigorous protest and led to a revolution. The second vice-president, General Pedro Diez Canseco and Colonel Mariano Ignacio Prado were the leaders of the movement against President Pezet, who, rather than plunge his country into civil war, resigned office, Colonel Prado being proclaimed dictator in November, 1865.