[1] It has been generally accepted that Barrios was born in San Juan Bautista, Paraguay,[2] although the baptismal document in the book of registries in the cathedral of that city does not give his place of birth and several biographers and authorities present evidence that he was actually born in nearby Villa Florida, Misiones, on the Tebicuary River, 30 km to the north[citation needed];[3] Barrios' diplomatic papers, found in 2019, give "Missiones" [sic] as the place of birth.

Eye-witness testimony from Lope Texera in Caracas Venezuela on April 18, 1932, declared that Barrios was "superior to Segovia whom I saw in London last year".

[4] Barrios sometimes performed in concert in traditional Paraguayan dress (he was partly of Guaraní origin), beginning in 1932 using the pseudonym of Nitsuga Mangoré ('Nitsuga' being Agustín spelled backwards, and 'Mangoré' being the name of a cacique of the South American indigenous group Timbú).

[6] After touring Europe in 1934-35, Barrios performed in Venezuela, Haiti, Cuba, Costa Rica, Nicaragua, El Salvador and Guatemala.

Several writers have suggested that Barrios revisited Mexico in 1939, but his immigration file with the Mexican government did not include an entry for him or his wife Gloria that year.

Ship passenger lists reveal that Barrios and his wife travelled as diplomats and arrived in Puerto Rico, a US territory, in January 1937.

[citation needed] He reportedly suffered a myocardial infarction in front of the US Embassy in Guatemala City on October 27, 1939, after it was discovered that he was travelling with phony diplomatic papers issued by his lifetime friend and Patron Tomas Salomoni.

[citation needed] During his performing years, Barrios only informally shared bits of his musical knowledge with his patrons Luis Pasquet, Martin Borda Pagola, Dionisio Basualdo, Bautista and Lalyta Almiron, and Raul Borges.

Fate and necessity had it such that he, after arriving in El Salvador, were to finally provide comprehensive guitar composition and performance instruction to selected students, mostly of Salvadoran nationality.

Among the folkloric influences, Barrios is known to have played such popular Paraguayan works as "Campamento Cerro León", "Londón Carapé", "Guyrá campana", "Mamá Cumandá".

[8] As an example, "Guyrá campana" is very interesting, since some of the material can be heard in parts of Barrios' recording of "Caazapá — Aire Popular Paraguayo".

Though "Guyrá campana" is traditional music, many maintain that it is very closely related to guitarist Carlos Talavera (from Caazapá), whom Barrios knew.

"[15] Outstanding pieces in his repertoire include: He also wrote a couple of poems: While in Paraguay, Barrios had access only to instruments of limited quality.

He is documented by photograph to have played the instruments of Spanish luthiers Manuel Ramirez, José Ramírez I, Enrique García, Francisco Simplicio, Domingo Esteso, Enrique Sanfeliu and Ricardo Sanchis Nacher, Brazilian maker Di Giorgio, and in print by Uruguayan maker Rodolfo Camacho.

On August 21, 2015, the film Mangoré – For the Love of Art was released in Asunción, based loosely on the life of Agustin Barrios, with a script and direction by the Chilean filmmaker Luis R. Vera.