In 1885 [his father] William George Frederick Cavendish-Bentinck (age 29) and [his mother] Ruth Mary St Maur (age 17) were married.
On 18 Jun 1897 Victor Cavendish-Bentinck 9th Duke of Portland was born to William George Frederick Cavendish-Bentinck (age 41) and Ruth Mary St Maur (age 29).
In 1948 [his father] William George Frederick Cavendish-Bentinck (age 92) died.
On 28 Jan 1953 [his mother] Ruth Mary St Maur (age 85) died.
On 13 Dec 1980 [his brother] Ferdinand Cavendish-Bentinck 8th Duke of Portland 1889-1980 (age 91) died. His brother Victor Cavendish-Bentinck 9th Duke of Portland (age 83) succeeded 9th Duke Portland, 10th Earl of Portland.
On 30 Jul 1990 Victor Cavendish-Bentinck 9th Duke of Portland (age 93) died without surviving male issue. He was buried at St Winifred's Church Holbeck. Duke Portland extinct. His half sixth cousin Henry Charles Bentinck 11th Earl of Portland 1919-1997 (age 70) succeeded 11th Earl of Portland.
Paternal Family Tree: Bentinck
Kings Wessex: Great x 25 Grand Son of King Edmund "Ironside" I of England
Kings Gwynedd: Great x 21 Grand Son of Owain "Great" King Gwynedd 1100-1170
Kings Seisyllwg: Great x 27 Grand Son of Hywel "Dda aka Good" King Seisyllwg King Deheubarth
Kings Powys: Great x 22 Grand Son of Maredudd ap Bleddyn King Powys 1047-1132
Kings England: Great x 12 Grand Son of King Henry VII of England and Ireland
Kings Scotland: Great x 18 Grand Son of Robert "The Bruce" I King Scotland
Kings Franks: Great x 21 Grand Son of Louis VII King Franks
Kings France: Great x 15 Grand Son of Charles "Beloved Mad" VI King France
Great x 4 Grandfather: Henry Bentinck 1st Duke Portland 1682-1726 11 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: William Bentinck 2nd Duke Portland 1709-1762 11 x Great Grand Son of Henry IV King England
Great x 4 Grandmother: Elizabeth Noel Duchess Portland 1688-1737
10 x Great Grand Daughter of Henry IV King England
Great x 2 Grandfather: William Cavendish-Bentinck 3rd Duke Portland 9 x Great Grand Son of King Edward IV of England
Great x 4 Grandfather: Edward Harley 2nd Earl of Oxford and Earl Mortimer 11 x Great Grand Son of King Edward III of England
Great x 3 Grandmother: Margaret Cavendish Harley 2nd Duchess Portland 1715-1785 8 x Great Grand Daughter of King Edward IV of England
Great x 4 Grandmother: Henrietta Cavendish Holles Countess of Oxford and Mortimer 1694-1755 7 x Great Grand Daughter of King Edward IV of England
Great x 1 Grandfather: Frederick Cavendish-Bentinck 9 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandfather: William Cavendish 3rd Duke Devonshire
10 x Great Grand Son of Henry IV King England
Great x 3 Grandfather: William Cavendish 4th Duke Devonshire 11 x Great Grand Son of Henry IV King England
Great x 2 Grandmother: Dorothy Cavendish 3rd Duchess Portland 1750-1794 8 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 4 Grandfather: Richard Boyle 3rd Earl Burlington
6 x Great Grand Son of King Henry VII of England and Ireland
Great x 3 Grandmother: Charlotte Elizabeth Boyle Marchioness Hartington 7 x Great Grand Daughter of King Henry VII of England and Ireland
Great x 4 Grandmother: Dorothy Savile Countess Burlington
11 x Great Grand Daughter of King Edward III of England
GrandFather: George Cavendish-Bentinck 10 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandfather: Christopher Lowther
Great x 3 Grandfather: William Lowther 1st Baronet
Great x 2 Grandfather: William Lowther 1st Earl Lonsdale
Great x 1 Grandmother: Mary Lowther 13 x Great Grand Daughter of King Edward III of England
Great x 4 Grandfather: Thomas Fane 8th Earl of Westmoreland 1701-1771
10 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: John Fane 9th Earl of Westmoreland 11 x Great Grand Son of King Edward III of England
Great x 2 Grandmother: Augusta Fane Countess Lonsdale 1761-1838 12 x Great Grand Daughter of King Edward III of England
Great x 4 Grandfather: Montagu Bertie
11 x Great Grand Son of King Edward III of England
Great x 3 Grandmother: Augusta Bertie 12 x Great Grand Daughter of King Edward III of England
Great x 4 Grandmother: Elizabeth Piers
Father: William George Frederick Cavendish-Bentinck 11 x Great Grand Son of King Henry VII of England and Ireland
Great x 1 Grandfather: Charles Powell Leslie
GrandMother: Prudence Penelope Cavendish-Bentinck nee Leslie
Victor Cavendish-Bentinck 9th Duke of Portland 1897-1990 12 x Great Grand Son of King Henry VII of England and Ireland
Great x 4 Grandfather: Edward Seymour 8th Duke Somerset 1695-1757 11 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: Webb Seymour 10th Duke Somerset 1718-1793 12 x Great Grand Son of King Edward III of England
Great x 2 Grandfather: Edward Seymour 11th Duke Somerset 13 x Great Grand Son of King Edward III of England
Great x 1 Grandfather: Edward Adolphus Seymour 12th Duke Somerset 13 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: James Hamilton 5th Duke Hamilton 2nd Duke Brandon
10 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: Archibald Hamilton 9th Duke Hamilton 6th Duke Brandon 11 x Great Grand Son of King Edward III of England
Great x 4 Grandmother: Anne Spencer Duchess Hamilton Duchess Brandon 1710-1771
Great x 2 Grandmother: Charlotte Hamilton Duchess Somerset 1772-1827 12 x Great Grand Daughter of King Edward III of England
Great x 4 Grandfather: Alexander Stewart 6th Earl Galloway
11 x Great Grand Son of King Edward III of England
Great x 3 Grandmother: Harriet Stewart Duchess Hamilton Duchess Brandon -1788 12 x Great Grand Daughter of King Edward III of England
GrandFather: Edward Adolphus Ferdinand Seymour 14 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: Richard Brinsley Sheridan
Great x 2 Grandfather: Thomas Sheridan
Great x 4 Grandfather: Thomas Linley
Great x 3 Grandmother: Elizabeth Anne Linley
Great x 1 Grandmother: 21 x Great Grand Daughter of King John "Lackland" of England
Great x 3 Grandfather: Colonel James Campbell of Ardkinglass
Great x 2 Grandmother: Caroline Henrietta Callander 20 x Great Grand Daughter of King John "Lackland" of England
Mother: Ruth Mary St Maur 15 x Great Grand Daughter of King Edward III of England
GrandMother: Rosina Elizabeth Swan Maid