While it is often claimed that the Cuban son emerged from rural Oriente and “invaded” Havana in the early 20th century, serious Cuban musicologists have clarifi ed that the true consolidation of the genre took place in Havana after around 1910–1920. Examination of 19th-century sources can help us trace with greater specifi city the origins of the particular musical features that distinguished the traditional son. Editions and descriptions of 1850s–1860s Havana contradanzas illuminate much about urban popular dance music of that milieu. In par-ticular, they reveal the presence of features typically associated with the son, such as melodies in duet format, the presence of clave as a structural rhythmic principle, certain distinctive syn-copations, short vocal refrains, and a bipartite structure consisting of a “song”-like fi rst section followed by an ostinato-based montuno-like second section, sometimes including a vocal refrain. Perusal of early recordings also suggests that the distinctively “anticipated” rhythms of the son existed in Oriente in only a seminal fashion, and evolved on the whole in Havana as the genre matured.