Commercial recordings in Brazil were first made in 1902 in Rio de Janeiro. During the first two decades of the 20th century, however, the recorded repertoire centered around the same musical genres established in the final decades of the previous century: for sung music, this meant modinhas, lundus, waltzes, and cançonetas; for instrumental music, this meant polkas, maxixes, marches, and tangos. During this period, sheet music for pianos and musical bands played a greater role in disseminating popular music than did mechanical recordings. This included dissemination by the medium of radio, which had begun in the country in the early 1920s but only expanded when its commercial operation was authorized in the 1930s. Of the leading musical genres of the period, samba and carnival marches (always sung) came into their own during the 1930s. Rio de Janeiro, at that time the capital of the republic, the cradle of the burgeoning phonograph recording industry, and the center of the still extant sheet music publishing business and radio broadcasting, is key to understanding Brazilian popular music of the time. During the entire period, however, migrants from other regions, especially from the northeastern states of Bahia, Pernambuco, and Ceará, made crucial contributions to popular music. These contributions became particularly significant during the final years of that decade with the success of baião, a sung musical genre with a distinct northeastern flavor whose influence would stretch into the 1950s.