On 18 Nov 1911 [his father] Alan Ian Percy 8th Duke Northumberland 1880-1930 (age 31) and [his mother] Helen Gordon-Lennox Duchess Northumberland (age 24) were married. She the daughter of Charles Gordon-Lennox 7th Duke Richmond (age 65) and . He the son of Henry George Percy 7th Duke Northumberland (age 65) and Edith Campbell Duchess Northumberland 1849-1913 (age 62).
On 15 Jul 1912 Henry George Alan Percy 9th Duke Northumberland was born to Alan Ian Percy 8th Duke Northumberland 1880-1930 (age 32) and Helen Gordon-Lennox Duchess Northumberland (age 25).
On 14 May 1918 [his grandfather] Henry George Percy 7th Duke Northumberland (age 71) died. His son [his father] Alan Ian Percy 8th Duke Northumberland 1880-1930 (age 38) succeeded 8th Duke Northumberland, 5th Earl Beverley, 11th Baronet Smithson of Stanwick in Yorkshire. [his mother] Helen Gordon-Lennox Duchess Northumberland (age 31) by marriage Duchess Northumberland.
On 23 Aug 1930 [his father] Alan Ian Percy 8th Duke Northumberland 1880-1930 (age 50) died. His son Henry George Alan Percy 9th Duke Northumberland (age 18) succeeded 9th Duke Northumberland, 6th Earl Beverley, 12th Baronet Smithson of Stanwick in Yorkshire.
On 21 May 1940 Henry George Alan Percy 9th Duke Northumberland (age 27) was killed in action. His brother [his brother] Hugh Algernon Percy 10th Duke Northumberland 1914-1988 (age 26) succeeded 10th Duke Northumberland, 7th Earl Beverley, 13th Baronet Smithson of Stanwick in Yorkshire.
Paternal Family Tree: Smithson
Kings Wessex: Great x 25 Grand Son of King Edmund "Ironside" I of England
Kings Gwynedd: Great x 22 Grand Son of Owain "Great" King Gwynedd 1100-1170
Kings Seisyllwg: Great x 28 Grand Son of Hywel "Dda aka Good" King Seisyllwg King Deheubarth
Kings Powys: Great x 23 Grand Son of Maredudd ap Bleddyn King Powys 1047-1132
Kings England: Great x 7 Grand Son of King Charles II of England Scotland and Ireland
Kings Scotland: Great x 18 Grand Son of Robert "The Bruce" I King Scotland
Kings Franks: Great x 22 Grand Son of Louis VII King Franks
Kings France: Great x 9 Grand Son of Henry IV King France
Great x 4 Grandfather: Hugh Percy 1st Duke Northumberland
Great x 3 Grandfather: Algernon Percy 1st Earl Beverley 8 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandmother: Elizabeth Seymour Duchess Northumberland 7 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 2 Grandfather: George Percy 5th Duke Northumberland 1778-1867 9 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandfather: Peter Burrell
Great x 3 Grandmother: Isabella Susan Burrell Countess Beverley 1750-1812
Great x 1 Grandfather: Algernon George Percy 6th Duke Northumberland 1810-1899 10 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandfather: John Stuart 3rd Earl Bute 8 x Great Grand Son of King Henry VII of England and Ireland
Great x 3 Grandfather: James Archibald Stuart-Wortley-Mackenzie 9 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandmother: Mary Wortley-Montagu Countess Bute 1718-1794 10 x Great Grand Daughter of King Edward III of England
Great x 2 Grandmother: Louisa Harcourt Stuart-Wortley-Mackenzie 10 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 4 Grandfather: David Cunynghame 3rd Baronet
Great x 3 Grandmother: Margaret Cunynghame
GrandFather: Henry George Percy 7th Duke Northumberland 11 x Great Grand Son of King Henry VII of England and Ireland
Great x 2 Grandfather: Henry Drummond
Great x 1 Grandmother: 15 x Great Grand Daughter of King Edward III of England
Great x 4 Grandfather: Robert Hay-Drummond Archbishop of York 1711-1776 12 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: Robert Hay-Drummond 10th Earl Kinnoul 13 x Great Grand Son of King Edward III of England
Great x 2 Grandmother: Henrietta Hay-Drummond 14 x Great Grand Daughter of King Edward III of England
Father: Alan Ian Percy 8th Duke Northumberland 1880-1930 12 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandfather: John Campbell 4th Duke Argyll 1693-1770 7 x Great Grand Son of King Henry VII of England and Ireland
Great x 3 Grandfather: John Campbell 5th Duke Argyll 8 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandmother: Mary Drummond Bellenden 10 x Great Grand Daughter of King Edward III of England
Great x 2 Grandfather: John Douglas Edward Henry Campbell 7th Duke Argyll 1777-1847 9 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandfather: John Barnaby Gunning
Great x 3 Grandmother: Elizabeth Gunning Duchess Hamilton and Argyll
Great x 4 Grandmother: Bridget Bourke
Great x 1 Grandfather: George Douglas Campbell 8th Duke Argyll 10 x Great Grand Son of King Henry VII of England and Ireland
Great x 3 Grandfather: John Glassel
Great x 2 Grandmother: Joan Glassel
GrandMother: Edith Campbell Duchess Northumberland 1849-1913 11 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 4 Grandfather: Granville Leveson-Gower 1st Marquess Stafford 10 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: George Granville Leveson-Gower 1st Duke Sutherland 8 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandmother: Louisa Egerton Countess Gower 1723-1761 7 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 2 Grandfather: George Sutherland Leveson-Gower 2nd Duke Sutherland 9 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandfather: William Sutherland 18th Earl Sutherland 1735-1766 8 x Great Grand Son of King Henry VII of England and Ireland
Great x 3 Grandmother: Elizabeth Sutherland Duchess Sutherland 19th Countess Sutherland 9 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 1 Grandmother: Elizabeth Georgiana Leveson-Gower Duchess Argyll -1878 10 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 4 Grandfather: Frederick Howard 5th Earl Carlisle 11 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: George Howard 6th Earl Carlisle 1773-1848 9 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandmother: Margaret Caroline Leveson-Gower Countess Carlisle -1824 8 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 2 Grandmother: Harriet Elizabeth Georgiana Howard Duchess Sutherland 10 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 4 Grandfather: William Cavendish 5th Duke Devonshire 8 x Great Grand Son of King Henry VII of England and Ireland
Great x 3 Grandmother: Georgiana Cavendish Countess Carlisle 1783-1858 9 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 4 Grandmother: Georgiana Spencer Duchess Devonshire 10 x Great Grand Daughter of King Henry VII of England and Ireland
Henry George Alan Percy 9th Duke Northumberland 1912-1940 7 x Great Grand Son of King Charles II of England Scotland and Ireland
Great x 4 Grandfather: George Lennox Great Grand Son of King Charles II of England Scotland and Ireland
Great x 3 Grandfather: Charles Lennox 4th Duke Richmond 2 x Great Grand Son of King Charles II of England Scotland and Ireland
Great x 4 Grandmother: Louisa Kerr 4 x Great Grand Daughter of King James I of England and Ireland and VI of Scotland
Great x 2 Grandfather: Charles Gordon-Lennox 5th Duke Richmond 1791-1860 3 x Great Grand Son of King Charles II of England Scotland and Ireland
Great x 4 Grandfather: Alexander Gordon 4th Duke Gordon 8 x Great Grand Son of King Henry VII of England and Ireland
Great x 3 Grandmother: Charlotte Gordon Duchess Richmond 1768-1842 9 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 4 Grandmother: Jane Maxwell Duchess Gordon
Great x 1 Grandfather: Charles Gordon-Lennox 6th Duke Richmond 4 x Great Grand Son of King Charles II of England Scotland and Ireland
Great x 4 Grandfather: Henry Bayly-Paget 1st Earl Uxbridge 12 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: Henry William Paget 1st Marquess Anglesey 13 x Great Grand Son of King Edward III of England
Great x 2 Grandmother: Caroline Paget Duchess Richmond 1796-1874 10 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 4 Grandfather: George Bussy Villiers 4th Earl Jersey 8 x Great Grand Son of King Henry VII of England and Ireland
Great x 3 Grandmother: Caroline Elizabeth Villiers Duchess Argyll 9 x Great Grand Daughter of King Henry VII of England and Ireland
GrandFather: Charles Gordon-Lennox 7th Duke Richmond 5 x Great Grand Son of King Charles II of England Scotland and Ireland
Great x 4 Grandfather: Fulke Greville 11 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: Charles Greville 12 x Great Grand Son of King Edward III of England
Great x 2 Grandfather: Algernon Frederick Greville 10 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandfather: William Cavendish-Bentinck 3rd Duke Portland 9 x Great Grand Son of King Edward IV of England
Great x 3 Grandmother: Charlotte Cavendish-Bentinck 9 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 4 Grandmother: Dorothy Cavendish 3rd Duchess Portland 1750-1794 8 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 1 Grandmother: Frances Harriett Greville Duchess Richmond 1824-1887 11 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 2 Grandmother: Charlotte Maria Cox
Mother: Helen Gordon-Lennox Duchess Northumberland 6 x Great Grand Daughter of King Charles II of England Scotland and Ireland