(1607-1647) Founder of Maryland and first proprietary governor, brother of Cecilius Calvert, born England; died Maryland. He commanded the expedition which established the settlement at Saint Mary's, 1634. The colonists were opposed by William Claiborne of Virginia, the conflicting claims being settled in favor of Lord Baltimore. In 1643 the governor went to England and upon his return, 1644, found the colony torn by disturbances resulting from the civilwar in England. After two years of confusion, Calvert regained control.