Sabatini was a proponent of basing historical fiction as closely as possible on history. Although Blood is a fictional character, much of the historical background of the novel is based on fact. The Monmouth rebels were sold into slavery as described in the book; and the shifting political alliances of the Glorious Revolution of 1688 are used in the novel as a plot device to allow Blood's return to respectability.
Sabatini based the first part of the story of Blood on Henry Pitman, a surgeon who tended the wounded Monmouth rebels and was sentenced to death by Judge Jeffreys, but his sentence was commuted to penal transportation to Barbados where he escaped and was captured by pirates. Unlike the fictional Blood, Pitman did not join them, and eventually made his way back to England where he wrote a popular account of his adventures. For Blood's life as a buccaneer, Sabatini used several models, including Henry Morgan and the work of Alexandre Exquemelin, for historical details.