Ralph George Algernon Percy, 12th Duke of Northumberland, was born 16 November 1956 in London, England, United Kingdom to Hugh Algernon Percy, 10th Duke of Northumberland (1914-1988) and Elizabeth Diana Montagu-Douglas-Scott (1922-2012) . He married Isobel Jane Miller Richard (1958) 21 July 1979 .
Children
| Name | Birth | Death | Joined with |
| Catherine Sarah Percy (1982) | |||
| George Dominic Percy (1984) | |||
| Melissa Jane Percy (1987) | |||
| Max Ralph Percy (1990) | |||
Footnotes (including sources)
| ‡ General |
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