The 1st Infantry Regiment "Los Patricios" (Regimiento de Infantería 1 "Los Patricios") is the oldest and one of the most prestigious regiments of the Argentine Army. The title is often shortened to the Patricians' Regiment (Regimiento de Patricios). Since the 1990s the regiment has been designated as air assault infantry. It is also the custodian of the Buenos Aires Cabildo, the welcoming party for visiting foreign dignitaries to Argentina and the escort, and honor guard battalion for the City Government of Buenos Aires. Since 22 September 2010, the Regiment's headquarters building has been a National Historical Monument following a declaration by the Argentine government on the occasion of the country's bicentennial year.

The regiment was formed as the Legión Patricia ("Patricians' Legion) from inhabitants of Buenos Aires in 1806 to fight against the British invasions of the Río de la Plata. Among some of its first members, it included a woman, the Alférez (approximately, second lieutenant) Manuela Pedraza, one of the heroes of the Defense of Buenos Aires in 1806. The regiment, therefore, existed prior to Argentine independence. Their first commander was Cornelio Saavedra. The regiment also fought in the May Revolution, the Cisplatine War, the Platine War, the Paraguayan War, the Dirty War, and the Falklands War.

Although the word "Patrician" is usually employed as a synonym for aristocrat, in the naming of the Regiment it meant "the sons of the homeland" (Spanish "Patria" meaning "homeland"). Indeed, the original members of the Regiment were not aristocrats but Criollos, who were much farther down in the social hierarchy of the time.

Prior to the arrival of British troops, Viceroy Santiago de Liniers decided that volunteers are drawn from the population of Buenos Aires muster at the Fort on 15 September 1806. More than 4,000 men appeared, who had to be enrolled in other military units.[1]

It was the largest and most powerful unit recruited for the Defense of Buenos Aires and, like other urban military units formed, was granted the privilege of electing its officers. The first election was held at the Consulate of Buenos Aires on November 8, 1806. Lieutenant Colonel Cornelio Saavedra was elected as head of the Corps or Legion and commander of the 1st Battalion, Esteban Romero was elected commander of the Second Battalion, and José Domingo Urien the Third Battalion commander. Manuel Belgrano was elected Sergeant Major (later replaced by Juan José Viamonte) and among other officers commissioned were Feliciano Chiclana, Vicente López y Planes, and Eustace Perdriel Gregorio Díaz Vélez.

St. Martin of Tours became the patron of the unit and on 9 November the regimental colors were consecrated with full ceremonial at the Cathedral of Buenos Aires along with that of the Arribeños Corps. The unit was then called the Buenos Aires Patrician Volunteer Urban Legion, with the status of a full Tercio or Colonial Regiment of Militia.

The Patricios Legion was made up of three battalions and the regimental HQ, with 23 companies of 50 men each (8 battalions I and III and seven in the II), with a total of 1,356 soldiers.

Composition of the Patricians Legion in 1807

Regimental Command