Like many slaves from Saint-Domingue (present-day Haiti) during the Haitian Revolution (1791–1804), Pablo Alí crossed the border to serve in the Spanish colonial army of Santo Domingo (present-day Dominican Republic) as a means of obtaining his freedom. In 1795Spain ceded Santo Domingo to France. Alí subsequently participated in the War of Reconquest, in which French troops were defeated and Santo Domingo was reunited with Spain (1809). In 1811 the Spanish throne named him first colonel and granted him a gold medal in recognition of his service to the Crown.
In 1820 Alí served as colonel of the Batallón de Morenos (Black Batallion) in Santo Domingo. After learning that his application for Spanish citizenship had been denied, in 1821 Alí pledged his loyalty to the insurrectionists, led by José de Núñez Cáceres and served as their chief military commander That same year ...