<P> After the Mexican Revolution, many haciendas had to let workers go, including mariachis . Groups began to wander and play for a fee, which obliged them to incorporate other music into their repertoires, including waltzes and polkas . It also required them to play in public venues . From the late 19th century to the 1930s, Mariachi groups were semi-professional . </P> <P> In the early 20th century, U.S., record companies began actively recording rural music in other parts of the world . One of these as a recording called Cuarteto Coculense by Columbia, Edison and Victor in 1908 and 1909, recognized as the "first" mariachi recordings . The music also gained attention in Mexico City when a wealthy hacienda family brought an early Mariachi from Cocula to play for President Porfirio Díaz in 1905 . </P> <P> The common perception of the music and look of mariachi developed in the 20th century, as the music was transformed from a regional rural folk music to an urban phenomenon that came to represent Mexico . The music was first introduced to Mexico City in 1905 . During this time, many farm workers moved to the city, including those from Jalisco, which settled around Plaza Garibaldi . These mariachi musicians developed new practices, such as performances in plazas and restaurants . However, it also continued its more traditional venues such as serenades, and performances at major family events . </P> <P> During this time, the Mexican government was heavily involved in cultural promotion as a way to create a unified Mexican identity after the end of the Mexican Revolution . One of these efforts was the promotion of mariachi as an international symbol of Mexican identity, first with radio and sound recordings and later with films . </P>

What is a group of street musicians in mexico