Question: When did Buenos Aires enact a centralist constitution?
About the article "Argentina", section "Independence and civil wars".

Candidate passages:
The Argentine War of Independence, which began in 1810, was soon followed by the Argentine Civil Wars, as the provinces had conflictive views over the national organization.
The federals supported the autonomy of the provinces, and the Unitarian party supported a political centralization of the country in Buenos Aires.
The Argentine Constitution of 1819, drafted by the Congress of Tucumán, was highly centralist.
It was abolished in 1820 after the federal victory at the battle of Cepeda.
The office of the Supreme Director of the United Provinces of the Río de la Plata, the head of state at the time, was abolished as well.
The provinces stayed united as a country by the Treaty of Pilar, but without any constitution or head of state for the time being.
This period is known as the "anarchy of the year XX".
The Treaty of Benegas between Buenos Aires and Santa Fe included an agreement to call for a new Constituent Assembly, which would work at the city of Córdoba.
The treaty did not mention the political system, which would be discussed at the assembly, nor the reaction to the Luso-Brazilian invasion of the Banda Oriental.
The assembly was attended by representatives of Buenos Aires, Santa Fe, Córdoba, Mendoza, San Juan, La Rioja, Santiago del Estero, Tucumán and San Luis.
However, the legal complaints of the representatives of Buenos Aires did not allow the Assembly to begin its work.
The assembly was closed shortly afterwards.
Buenos Aires, Santa Fe, Entre Ríos and Corrientes signed the Quadrilateral Treaty, to call a new Constituent Assembly, this time in Buenos Aires.
Again, it did not specify the political system.
The new assembly was convened in Buenos Aires on February 27.
As the number of representatives was proportional to the population, Buenos Aires had the highest number.
Twelve of the thirteen provinces accepted to hold the Congress in Buenos Aires; San Luis proposed Tucumán. 
Early conflicts against centralized rule.
Regionalism had long marked the relationship among the numerous provinces of what today is Argentina, and the wars of independence did not result in national unity.
The establishment of the League of the Free Peoples by the Eastern Bank of the Uruguay River and four neighboring provinces in 1814 marked the first formal rupture in the United Provinces of South America that had been created by the 1810 May Revolution.
The Battle of Cepeda (1820) thwarted the goal of Buenos Aires leaders to govern the country under the Argentine Constitution of 1819, and following a series of disorders and a short-lived Constitutional Republic led by Buenos Aires centralist Bernardino Rivadavia in 1826 and 1827, the United Provinces established in 1810 again became divided, and the Province of Buenos Aires would emerge as the most powerful among the numerous semi-independent states. 
Historical overview.
Regionalism had long marked the relationship among the numerous provinces of what today is Argentina, and the wars of independence did not result in national unity.
Following a series of disorders and a short-lived Constitutional Republic led by Buenos Aires centralist Bernardino Rivadavia in 1826 and 1827, the Province of Buenos Aires would function as a semi-independent state amid an internecine civil war.
An understanding was entered into by Buenos Aires Governor Juan Manuel de Rosas and other Federalist leaders out of need and a shared enmity toward the still vigorous Unitarian Party.
The latter's 1830 establishment of the Unitarian League from nine western and northern provinces would force Buenos Aires, Corrientes and Entre Ríos Provinces into the Federal Pact of 1831, and enabled the overthrow of the Unitarian League.
The granting of the sum of public power to Rosas in 1835 established a dynamic whereby leaders ("caudillos") from the hinterland provinces would delegate certain powers, such as foreign debt payment or the management of international relations to the Buenos Aires leader.
The Argentine Confederation thus functioned, albeit amid ongoing conflicts, until the 1852 Battle of Caseros, when Rosas was deposed and exiled. 
 Buenos Aires CBD, the central business district of Buenos Aires  Greater Buenos Aires ("Greater Buenos Aires"), the city of Buenos Aires and the surrounding conurbation, with 12 million inhabitants  Province of Buenos Aires, one of Argentina's 23 constituent provinces, which does include most of Greater Buenos Aires but does not include the Federal Capital  State of Buenos Aires, a historical period when the province of Buenos Aires acted as a nominally independent state from the Argentine Confederation  Autódromo Oscar Alfredo Gálvez, a racing circuit near Buenos Aires, commonly known as ""Buenos Aires"" by motor racing fans  Lake Buenos Aires, Argentina  Buenos Aires Lake (Bolivia)  Buenos Aires National Wildlife Refuge, Arizona  Buenos Aires, Pernambuco, Brazil  Buenos Aires, Cauca, Colombia  Buenos Aires (canton), Puntarenas Province, Costa Rica  Buenos Aires, Rivas, Nicaragua  Little Buenos Aires, Miami Beach, Florida  Buenos Aires (Independencia), Santo Domingo, Dominican Republic  Buenos Aires (Puerto Rico), in Santurce, Puerto Rico  Buenos Aires, Trujillo, Peru  Buenos Aires District, Picota, Peru  Buenos Aires District, Morropón, Peru  
Mariano Vera was a "caudillo" and governor of the province of Santa Fe, Argentina, between 12 April 1816 and 23 July 1818.
Vera was a supporter of federalism, against the idea of a centralized government.
After the proclamation of the first national government junta, in 1810, Santa Fe was ruled by lieutenant governors sent from the capital Buenos Aires, which did not sit well with many local citizens and worked to increase the influence of the federalist leader José Gervasio Artigas, based on the Eastern Bank (today's Uruguay).
The Supreme Directorship invaded Santa Fe in March 1815; the next month Artigas liberated it and set up Francisco Antonio Candioti as governor.
Candioti was in turn ousted and replaced by the centralist Juan Francisco Tarragona.
Vera and other political leaders, notably Estanislao López, gathered the support of Candioti's followers, and rebelled in March 1816, helped by Artigas's troops coming via Paraná, Entre Ríos.
Buenos Aires's occupation forces under Juan José Viamonte were defeated, and Mariano Vera was elected governor of Santa Fe.
Soon afterwards, the governments of Santa Fe and Buenos Aires signed treaties by which Buenos Aires acknowledged Santa Fe as a "free and independent" entity until a national constitution was drawn by the upcoming Congress of Tucumán.
Santa Fe would send a deputy to the Congress, and the economically essential roads passing through Santa Fe towards Peru and Chile would not be closed to traffic.
Governor Vera thus adopted a pragmatical equilibrium stance between Artigas and Buenos Aires, prioritizing the interests of the province rather than ideological concerns.
Santa Fe, an agricultural region beside the Paraná River, needed to have access to the port of Buenos Aires and at the same time could not allow Buenos Aires to centralize power, which would make its port the only one allowed to function (as it happened decades later, during the rule of Juan Manuel de Rosas).
However, the government of Buenos Aires delayed the ratification of the treaties, and started a campaign to retake power in Santa Fe, first through a failed military operation in August 1816, and then giving support to Vera's political enemies and to uprisings in Santa Fe and other provinces.
Vera turned decidedly to support the cause of Artigas, sending troops, guns and supplies to the Eastern Bank (modern-day Uruguay).
The hostilities continued.
In March 1818 Buenos Aires sent new military missions to Santa Fe and Entre Ríos.
Governor Vera, weakened, was eventually ousted by his former ally Estanislao López, who would prevail over the centralist army and rule the province for twenty years.