 He was a direct descendant of the Lords Baltimore, proprietary governors of the Province of Maryland from 1631 until 1776.Calvert was born on August 23, 1808 at his family's estate at Riversdale, Maryland.His mother was Rosalie Eugenia Stier (1778–1821), the daughter of a wealthy Flemish aristocrat, Baron Henri Joseph Stier (1743–1821) and his wife Marie-Louise Peeters.