Complex sentence: Initially descendants of French men and African slaves, and then often marrying within their own mixed-race community, some achieved wealth and power, particularly in the French colony of Saint-Domingue, which achieved independence in 1804 as the Republic of Haiti.
Split into simpler sentences: Initially descendants of French men and African slaves, and often marrying within their own mixed-race community, some achieved wealth and power. Free people of color were leaders in the French colony of Saint-Domingue, which achieved independence in 1804 as the Republic of Haiti.