Benedict Swingate Calvert was a planter, politician and a Loyalist in Maryland during the American Revolution. He was the son of Charles Calvert, 5th Baron Baltimore, the third Proprietor Governor of Maryland (1699–1751). His mother's identity is not known, though one source speculates that she was Melusina von der Schulenburg, Countess of Walsingham. As he was illegitimate, he was not able to inherit his father's title or estates, which passed instead to his half brother Frederick Calvert, 6th Baron Baltimore (1731–1771). Benedict Calvert spent most of his life as a politician, judge and planter in Maryland, though Frederick, by contrast, never visited the colony. Calvert became wealthy through proprietarial patronage and became an important colonial official, but he would lose his offices and his political power, though not his land and wealth, during the American Revolution.

Charles Calvert, 5th Baron Baltimore, was a British nobleman and Proprietary Governor of the Province of Maryland. He inherited the title to Maryland aged just fifteen, on the death of his father and grandfather, when the colony was restored by the British monarchy to the Calvert family's control, following its seizure in 1688. In 1721 Charles came of age and assumed personal control of Maryland, travelling there briefly in 1732. For most of his life, he remained in England, where he pursued an active career in politics, rising to become Lord of the Admiralty from 1742 to 1744. He died in 1751 in England, aged 52.