A combined expedition of Argentine and Chilean patriots under General José de San Martín landed south of Lima in 1820 but did not attack the city. Faced with a naval blockade and the action of guerrillas on land, Viceroy José de la Serna e Hinojosa evacuated its capital in July 1821 to save the Royalist army. Fearing a popular uprising and lacking any means to impose order, the city council invited San Martín to enter Lima and signed a Declaration of Independence at his request. However, the war was not over; in the next two years, the city changed hands several times.