While the earliest known primary documents acknowledging the existence of mariachi only date back to the middle of the 19th century (found in a letter written by a priest in 1852), the mystery surrounding the origins of the name "mariachi" is even more puzzling. Many theories regarding the name origin are in circulation, the most sensational being:
Mariachi originated when Hernán Cortes invaded what today is considered modern Mexico in the year 1519. With him he brought professional musicians whose instruments of choice included the harp and the vihuela (a smaller version of the guitar), which would later represent the archetypes of the same instruments employed by later mariacheros. These instruments were fused with native and African sounds. This cultural blend produced what was largely referred to as "mestizo folk music", a category under which mariachi music fell. Again, lack of documentation regarding mestizo fold music leads scholars to ponder upon the detailed circumstances associated with this musical genre. Although many cite Jalisco as being the location of the birthplace of mariachi, the true birthplace of mariachi has yet to be pinpointed; to date, the general birthplace of mariachi is credited to a region spanning a larger portion of what is now modern day western Mexico, which encompasses not only Jalisco, but also the states of: Nayarit, Zacatecas, Aguascalientes, Guanajuato, Michoacán, and Colima.
By the latter half of the 1800´s Mariachi had evolved into festive dance music, where, during a rural fiesta for fandango, couples would dance sones and jarabes. An incorporation of Spanish, Mexican, and African influence, the son experienced its peak popularity during this time. In the early 1900´s, when radio and records were the standard form of entertainment throughout not only Mexico, but most of North America, mariachi songs were recorded. It was then that violins and trumpets were added to the ensemble. These instruments along with the guitar and the vihuela created are now taken to be the standard mariachi sound. However, there is a dichotomy between the mariachi of the city (el pueblo) and the mariachi of the rural regions (el rancho). Rural mariachi includes the traditional sones and jarabes, along with pokes, waltzes, foxtrots and pasodobles. Mariachi has even infiltrated the church, being used for wakes, processions and other religious ceremonies. On the other hand, urban mariachi revolves around the nature of the son in its melody, and is generally referred to as ranchera music. Interestingly enough, ranchera music is usually performed by a mariachi band or conjunto, bearing all characteristics similar to that of the corrido.