“She was part of this really complex maritime system of watermen, sailors, and dockworkers that formed this broad communications network that could get messages back and forth from North to South, a whole world that she tapped into that was entirely beyond the gaze of white people,” said Kate Clifford Larson, author of Bound for the Promised Land: Harriet Tubman, Portrait of an American Hero and a historian who served as a consultant on the film. Tubman was the first woman to lead American soldiers in combat, Larson said, and remains one of the few to do so.