At the end of 1940, according to an article in a journal of INAH, the radio station XEW pressed the Mariachi Vargas de Tecalitlán to add a trumpet: “se le ‘obliga’ al Mariachi Vargas a incluir la trompeta” (the Mariachi Vargas is “obliged” to include the trumpet).
The trumpet was not completely new. A recording of La Negra made in 1937 by the Mariachi Tapatío de José Marmolejo already had one. The article describes the result as the arrival of the trumpet as a canonical and indispensable instrument of the mariachi.