sentences:  These forces were unified into the Batallón de Pardos y Morenos, also known as the Batallón Castas, at a strength of 9 companies, plus 4 auxiliary slave companies, at the time of the first British invasions of the River Plate.Regimental status was gained in 1810, and the new Regimento de Pardos y Morenos participated in the Argentine War of Independence.The British invasion of the Río de la Plata of 1806 followed an uprising of Argentine's slave population in Buenos Aires encouraged by the rise of the movement for abolition of slavery in Britain.