“El entrerriano” is regarded as the first tango in history. It was composed in 1887 by pianist Rosendo Mendizábal under the pseudonym of A. Rosendo. Along with other early compositions such as “Don Juan“ (1899) and “El cholco” (1903), it contributed to establish and consolidate the musical structure of tango.
Many others tangos had been composed and popularized before 1887, but offered the first printed tango partitions with registered author.  It is also the oldest tango still present in today’s repertoire and this is why it is regarded as the first tango in history.
“El entrerriano” means “the one who comes from the province of Entre Rios“. It was dedicated to Ricardo Sergovia, a member of a young men’s club which regularly held their parties at lo de Maria la Vasca, a well known casa de baile where Rosendo Mendizábal had become the regular pianist. Since copyrights didn’t exist at the end of the 19th century, it was common for composers to dedicate their work to someone who could pay them in return for the favour, in this case Ricardo Sergovia who was born in the province of Entre Rios. This is why the first tango in history is entitled “El entrerriano”. 
Like most early tango compositions, “El entrerriano” is essentially an instrumental piece. Many different lyrics were written for it over the years by A. Semino y S. Retondaro, Planells y Amor, Julián Porteño and Homero Expósito but these were rarely used or recorded. Ángel Villoldo also added some verses to “El entrerriano” for Pepita Avellaneda in 1900:
“A mí me llaman Petita, ay ay, de apellido Avellaneda, ay ay, famosa por la milonga, y conmigo no hay quien pueda”
Unfortunately Rosendo Mendizábal died in 1913 leaving no recordings. That same year “El entrerriano” was recorded twice, first by Genaro Espósito and later by Eduardo Arola under the labels Atlanta and Odeon respectively. Other early recordings of “El entrerriano” include that of Ciriaco Ortiz with his trio and another recording by the municipal band.
Many versions of “El entrerriano” were recorded by orchestras of the guardia vieja and of the golden age including those of Francisco Canaro, Julio de Caro, Osvaldo Fresedo, Juan D’arienzo, Alfredo de Angelis, Anibal Troilo and Osvaldo Pugliese. Astor Piazzolla recorded his own version of the first tango in history with his Octeto Buenos Aires.
“El entrerriano” was performed in the Argentine sound film “Tango” (1933) by the Orquesta de la guardia vieja of Ernesto Ponzio and Juan Carlos Bazan. π
 Del Priore, Oscar, and Irene Amachástegui. Cien tangos fundamentales. Buenos Aires: Aguilar, 1998. Print.
 Selles, Roberto. El Entrerriano. La historia de “El entrerriano” y sus principales grabaciones. Todotango. Online. http://www.todotango.com/historias/cronica/380/El-entrerriano-Historia-de-El-entrerriano-y-sus-principales-grabaciones/
 Selles, Roberto. “El tango y sus dos primeras decadas (1880- 1900)” in La historia del tango: Primera epoca. Buenos Aires: Corregidor. 1977. Print.