tariff disagreement, and continued when former Chilean president General Ramón Freire managed to obtain a small subsidy from the Confederation government to equip a frigate and try to wrestle power from the Prieto administration. After the failure of the expedition, the Chilean government became openly hostile towards the Confederation. Raid on Callao and Chilean declaration of war After the Freire expedition, Portales decided to take the offensive and staged a surprise raid to prevent further interference by the Confederation government in Chilean internal affairs. He ordered a raid on the Confederate fleet that was stationed in the port of Callao. During a silent attack on the night of August 21, 1836, the Chileans managed to capture three confederate ships: the Santa Cruz, Arequipeño and Peruviana. Instead of immediately going to war, Marshal Santa Cruz tried to negotiate with Chile. The Chilean Congress sent Mariano Egaña as plenipotentiary to negotiate a treaty based on several points: the payments of the outstanding international debts owed by Peru to Chile, the limitation of the outstanding armies, commercial agreements, indemnization to Chile for the Freire expedition, and the dissolution of the Confederation. Santa Cruz agreed to everything but the dissolution. Chile responded by declaring war on December 28, 1836. International situation and Argentine declaration of war The international situation was not favorable to Chilean interests. Marshal Santa Cruz and the Confederation had been diplomatically recognized by the principal world powers with interests in the region (Great Britain, France and the United States), while Chile's allies, Argentina and Ecuador, had decided to remain neutral in the conflict. Nonetheless, the continued interference of Santa Cruz in Argentina's internal affairs moved this country also to declare war, on May 9, 1837. Even though Chile and Argentina were acting against the same perceived threat, both countries went to war separately and were going to act separately during the whole course of it. In 1837, Felipe Braun, one of Santa Cruz's most capable generals and high decorated veteran of the war of independence, defeated an Argentine army sent to topple Santa Cruz. To further aggravate the Chilean position, public opinion there was totally opposed to a war they did not understand. Assassination of Portales The Chilean government, in order to bolster its standing, immediately imposed martial law, asking for (and obtaining) extraordinary legislative powers from Congress. Early in 1837 a Court Martial Law was approved, and all citizens became