Castilla was succeeded by his old friend and companion in arms, General San Roman, a straightforward soldier who resembled his chief in his unquestioning obedience to lawful authority, but whose unfortunate death six months after his inauguration prevented him from demonstrating whether he possessed the same statesmanlike qualities. Vice-President Pezet peacefully took his place. Castilla had encouraged foreign immigration into the coast valleys, so admirably adapted to cotton and sugar, but where labour was scarce. Chinese coolies had come in large numbers, and the flattering offers had also attracted some Europeans. Among the latter were seventy Basque families, who shortly claimed that they were badly treated. Making a protest against a breach of contract committed by the proprietor of the estate on which they were working, they were attacked and some of them killed. The criminals escaped punishment, and the Spanish government made an international question of the affair, finally demanding an apology and three millions of dollars as indemnity. This being refused Spain broke off diplomatic relations and sent a powerful fleet, which seized the Chincha guano islands. Too weak alone to bid defiance to the Spanish ships, Pezet temporised, meanwhile asking Chile for help, and hoping for the early arrival of war-ships ordered in Europe. But the Spaniards pressed him so hard that he thought himself forced to yield to their demands. He concluded an agreement derogatory to the national honour, and a terrific outburst of public indignation followed. Prado, prefect of Arequipa, made preparations to march on Lima and depose the pusillanimous president; the Chileans, who had meantime determined to join in resistance to Spanish aggression, supported the insurrection; the terrible old Castilla went himself to the presidential mansion and gave Pezet a sound rating. The latter gave in and offered his resignation. Prado became supreme chief, issued a declaration of war against Spain, and signed a treaty of alliance with Chile. During the absence of the Spanish fleet the batteries at Callao were heavily reinforced, and an immense force of volunteers flocked to man the guns. When the Spanish ships appeared and, gallantly running into range, opened fire on the 2d of May, 1866, they were met by a determined resistance. Though the Peruvians suffered most severely--two thousand being killed and wounded--their opponents were unable to effect a landing or obtain the slightest concession, and their ships were so badly damaged that they abandoned further hostilities.