José de San Martín declares the independence of Peru

Background. The liberation of Peru was prepared by a treaty between Argentina and Chile in 1819. The Liberating Expedition, commanded by San Martín, arrived in 1820. Facing naval blockades and guerrilla actions, the Royalist Viceroy José de la Serna was forced to evacuate Lima in July 1821, creating the conditions for San Martín to assume authority and declare independence.

Declaration of Independence. San Martín was appointed Protector of Peru on 12 July 1821 after seizing partial control of Lima. The Act of Independence was signed on 15 July 1821. With the support of northern provinces and the siege of El Callao, San Martín officially declared the independence of Peru on 28 July 1821, dissolving the Spanish Viceroyalty.

Immediate Aftermath. Following the declaration, Lima was granted the title of Heroic and Courageous City of the Free in September 1821. The event marked the emergence of Peru as an independent state. However, disagreements with Simón Bolívar later divided patriot forces, leading to San Martín's withdrawal in 1822, though this falls outside the immediate scope of the declaration itself.