Question: Which official name of Argentina predated the Argentine Constitution of 1853?
Context: The San Nicolás Agreement (Spanish: Acuerdo de San Nicolás ) was a pact signed on May 31, 1852 and subscribed by all but one of the 14 provinces of the United Provinces of the River Plate (the exception was Buenos Aires).  The treaty consisted of 19 articles, and its goal was to set the bases for the national organization of the young Argentine state.  It also served as precedent to the sanction of the Argentine Constitution of 1853. The office of Vice President of Argentina is the second highest political position in Argentina, and first in the line of succession to the Presidency of Argentina.  The office was established with the enactment of the Argentine Constitution of 1853. The Argentine Confederation (Spanish: "Confederación Argentina") is one of the official names of Argentina according to the Argentine Constitution, Article 35.  It was the name of the country from 1831 to 1852, when the provinces were organized as a confederation without a head of state.  The governor of Buenos Aires Province (Juan Manuel de Rosas during most of the period) managed foreign relations during this time.  Under his rule, the Argentine Confederation resisted attacks by Brazil, Bolivia, Uruguay, France and the UK, as well other Argentine factions during the Argentine Civil Wars. The Pact of San José de Flores ("Pacto Unión San José de Flores", or "Pacto de Unión Nacional") was a treaty signed between the Argentine Confederation and the State of Buenos Aires on November 11, 1859, on the aftermath of the Battle of Cepeda.  It established guidelines for the entry of the latter into the Confederation, and Buenos Aires' acceptance of the Argentine Constitution of 1853. The Treaty of Pilar (in Spanish, "Tratado del Pilar") was a pact signed among the rulers of the Argentine provinces of Santa Fe, Entre Ríos and Buenos Aires, which is recognized as the foundation of the federal organization of the country.  It was signed in the city of Pilar, Buenos Aires on 23 February 1820 by governor Estanislao López for Santa Fe, "caudillo" Francisco Ramírez for Entre Ríos, and provisional governor Manuel de Sarratea for Buenos Aires, after the dissolution of the national government caused by the Battle of Cepeda.  A reference to it was included in the Preamble of the Argentine Constitution of 1853 as one of the "pre-existing pacts" fulfilled by it. The Argentine Army ("Ejército Argentino", EA) is the land armed force branch of the Armed Forces of the Argentine Republic and the senior military service of the country.  Under the Argentine Constitution, the President of Argentina is the Commander-in-Chief of the Armed Forces, exercising his or her command authority through the Minister of Defense. Argentina has had many different types of heads of state, as well as many different types of government.  During Pre-Columbian times the territories that today form Argentina were inhabited by nomadic tribes, without any defined government.  During the Spanish colonization of the Americas, the King of Spain retained the ultimate authority over the territories conquered in the New World, appointing viceroys for local government.  The territories that would later become Argentina were first part of the Viceroyalty of Peru, and then the Viceroyalty of the Río de la Plata.  The May Revolution started the Argentine War of Independence by replacing the viceroy Baltasar Hidalgo de Cisneros with the first national government.  It was the Primera Junta, a junta of several members, which would grow into the Junta Grande with the incorporation of provincial deputies.  The size of the Juntas gave room to internal political disputes among their members, so they were replaced by the First and Second Triumvirate, of three members.  The Assembly of the Year XIII created a new executive authority, with attributions similar to that of a head of state, called the Supreme Director of the United Provinces of the Río de la Plata.  A second Assembly, the Congress of Tucumán, declared independence in 1816 and promulgated the Argentine Constitution of 1819.  However, this constitution was repealed during armed conflicts between the central government and the "Federal League" Provinces.  This started a period known as the "Anarchy of the Year XX", when Argentina lacked any type of head of state. The Argentine Constitution of 1853 was the first constitution of Argentina approved with the support of the governments of the provinces —though without that of the Buenos Aires Province, who remained separated of the Argentine Confederation until 1859, after several modifications to the original constitution and the return of the power to Buenos Aires Unitarians— sanctioned in May 1853 by the Constitutional Convention gathered in Santa Fe, and promulgated by the provisional Director of the national executive government Justo José de Urquiza from the Federals.  Following the short-lived constitutions of 1819 and 1826, it was the third constitution in the history of the country. Elementos de derecho público provincial Argentino (Spanish: "Elements of Argentine provincial civic law" ) is an 1852 Argentine book by Juan Bautista Alberdi.  It is a comparison between the Argentine Constitution of 1826 and the United States Constitution.  The book complements his other book "Bases y puntos de partida para la organización política de la República Argentina" (Spanish: "Bases and starting points for the political organization of the Argentine republic" ), which influenced the Constitution of Argentina of 1853. The Argentine Constitution of 1826 was a short-lived Constitution of Argentina drafted during the Argentine Civil Wars.  Bernardino Rivadavia was appointed President of Argentina under this constitution.  It was rejected by most Argentine provinces, and then abolished.
Answer: The Argentine Confederation