The Spanish expeditionary force, which departed from Algeciras, was composed of 36,000 men, 65 pieces of artillery, and 41 ships, which included steamships, sailboats, and smaller vessels. General Leopoldo O'Donnell personally took charge of the expedition and divided these forces into three corps. These were commanded by General The 5th Marqués de Torreblanca, General Antonio Ros de Olano and General Ramón de Echagüe. Reserves were placed under the command of General The 1st Conde de Reus. Admiral Segundo Díaz Herrero commanded the fleet.