Early tango was played by immigrants in Buenos Aires, then later in Montevideo. The first generation of tango players from Buenos Aires was called "Guardia Vieja" (the Old Guard). It took time to move into wider circles; in the early 20th century, it was the favorite music of thugs and gangsters who visited brothels, in a city with 100,000 more men than women (in 1914). The complex dances that arose from such rich music reflect how the men would practice the dance in groups, demonstrating male sexuality and causing a blending of emotion and aggressiveness. The music was played on portable instruments: flute, guitar, and violin trios, with bandoneón arriving at the end of the 19th century. The organito, a portable player-organ, broadened the popularity of certain songs. Eduardo Arolas was the major driver of the bandoneón's popularization, with Vicente Greco soon standardizing the tango sextet as consisting of piano, double bass, two violins, and two bandoneóns.