The Calvert Family
The Calverts were from a Yorkshire farming background, but the 1st Baron rose to become Secretary of State to James I. He married well: his first wife Anne Mynne (1579-1622) was descended from King Edward III. Most American Calverts are descended from either Leonard Calvert (1610-47), George’s 2nd son and the first Governor or Maryland, or from Benedict Swingate Calvert (1724-88) the natural son of Charles Calvert, 5th Baron Baltimore.
5th Baron Charles also had 2 sons by a French lady (Cecil Bressan) who lived in London. He made provision for both boys in his will, and gave them the Calvert surname. The younger son, Rev Augustus Bressan Calvert (1742-1812), still has living descendants in the UK and New Zealand:
Descendants of Augustus Bressan Calvert