Tomás Guido. (November 1, 1788, Buenos Aires–September 14, 1866) was a general in the Argentine War of Independence, a diplomat and a politician.
Tomás Guido was the son of a Spanish merchant Pedro Guido y Sanz and his wife Juana Aoiz y Martínez. He attended San Carlos College, but was forced to give up his studies by an economic crisis.
Guido saw his first military action in 1806 when he helped to defend Buenos Aires from the British invaders. He later went on to participate in the May Revolution in 1810.
In 1811 Guido became the secretary for Dr Mariano Moreno on his journey to England. In 1812 Guido returned to Argentina to work as a secretary in the Ministry of War, later he moved to Charcas to work as a secretary for Francisco Ortiz de Ocampo. Later he travelled to Tucumán where he joined José de San Martín y Manuel Belgrano, where he worked as the chief Secretary of the Army, working with San Martín to plan the campaign to liberate Chile and Peru.
On May 20, 1816 Guido presented Antonio González Balcarce with Memoria, which was based on his memories of conversations with San Martín in Saldán, Córdoba about the military, economic and political details of the Maitland Plan.
After the victory at the Battle of Chacabuco (February 12, 1817). General San Martín named Guido as Lieutenant Colonel, but he continued doing the job of Chief Secretary of the Army and Navy. During the ceremony to mark the official declaration of Chilean independence on February 12, 1818, Guido played the role of flagbearer.