Between 1842 and 1848, Garibaldi defended Montevideo against forces led by Oribe. In 1845, he managed to occupy Colonia del Sacramento and Martín García Island, and led the controversial sack of Gualeguaychú during the Anglo-French blockade of the Río de la Plata. Adopting amphibious guerrilla tactics, Garibaldi later achieved two victories during 1846, in the Battle of Cerro and the Battle of San Antonio del Santo.