sentences:  The Afro-Argentine population resulting from the slave trade during the centuries of Spanish domination of the Viceroyalty of the Río de la Plata had a major role in Argentine history.During the 18th and 19th centuries they comprised up to fifty percent of the population in some provinces, and had a deep impact on national culture.Some theories hold it that in the 19th century the Afro-Argentine population declined sharply due to several factors, such as the Argentine War of Independence (c. 1810–1818), high infant mortality rates, low numbers of married couples in this ethnic group, the Paraguayan War, cholera epidemics in 1861 and 1864, and a yellow fever epidemic in 1871.