Complex sentence: David Hamilton Jackson (1884-1946) was resident of the United States Virgin Islands which was under the rule of Danish West Indies who was an important figure in the struggle for increased civil liberties and workers' rights on the islands.
Split into simpler sentences: David Hamilton Jackson (1884-1946) was a resident of the United States Virgin Islands. Jackson was an important figure in the struggle for increased civil liberties and workers' rights on the islands.