This work was based on research by the “Historical Information Center on the Spanish Florida” (Centro de Documentación Histórica de la Florida Colonial Hispana), 3220 NW 7 St., Miami, Fl 33127, EE. UU., where there are 162,000 digital documents of that period, and also 12,000 original pieces. The research was centered on the “War of Jenkins’ ear” and during that period, the “Battle of Bloody Marsh” (July, 7th 1742), also known as the “Battle of Saint Simmons’ island”, which consisted of skirmishes between the Spanish and British troops in the marsh with the same name of the island – located in southeast Georgia (United States). The combats were part of the “War of Jenkins’ ear” between Spain and Great Britain, beginning in 1739. Other documents preserved in the Collections of the Georgia Historical Society, Savannah, 1909 have also been consulted. Following the classical methodology in historical research, the analyticsynthetic method was applied using the heuristic synthesis in order to get to the hermeneutic synthesis, and also to a chronological study of the events that culminated in one of the more complex defeats suffered by the British troops and their native auxiliaries in the 18th century in North- America.