On 05 Jul 1739 [her father] William Ponsonby 2nd Earl Bessborough (age 35) and [her mother] Caroline Cavendish Countess Bessborough 1719-1760 (age 20) were married. His younger brother [her uncle] John Ponsonby (age 26) would marry her younger sister [her aunt] Elizabeth Cavendish (age 13) four years later. She the daughter of William Cavendish 3rd Duke Devonshire (age 40) and (age 40). He the son of Brabazon Ponsonby 1st Earl Bessborough 1679-1758 (age 60) and Sarah Margetson.
On 14 Oct 1742 Catherine Ponsonby Duchess St Albans was born to William Ponsonby 2nd Earl Bessborough (age 38) and Caroline Cavendish Countess Bessborough 1719-1760 (age 23).
On 04 Jul 1758 [her grandfather] Brabazon Ponsonby 1st Earl Bessborough 1679-1758 (age 79) died. His son [her father] William Ponsonby 2nd Earl Bessborough (age 54) succeeded 2nd Earl Bessborough. [her mother] Caroline Cavendish Countess Bessborough 1719-1760 (age 39) by marriage Countess Bessborough.
On 20 Jan 1760 [her mother] Caroline Cavendish Countess Bessborough 1719-1760 (age 40) died. Monument in Derby Cathedral [Map] sculpted by John Michael Rysbrack (age 65).
On 02 Oct 1762 Charles Spencer (age 22) and [her future sister-in-law] Mary Beauclerk (age 18) were married. He the son of Charles Spencer 3rd Duke Marlborough and Elizabeth Trevor Duchess Marlborough 1713-1761. She a great granddaughter of King Charles II of England Scotland and Ireland. 
On 04 May 1763 Aubrey Beauclerk 5th Duke St Albans 1740-1802 (age 22) and Catherine Ponsonby Duchess St Albans (age 20) were married. She the daughter of William Ponsonby 2nd Earl Bessborough (age 59) and Caroline Cavendish Countess Bessborough 1719-1760. He a great grandson of King Charles II of England Scotland and Ireland.
On 21 Aug 1765 [her son] Aubrey Beauclerk 6th Duke St Albans was born to [her husband] Aubrey Beauclerk 5th Duke St Albans 1740-1802 (age 25) and Catherine Ponsonby Duchess St Albans (age 22). He a great x 2 grandson of King Charles II of England Scotland and Ireland.
On 18 Dec 1766 [her son] William Beauclerk 8th Duke St Albans 1766-1825 was born to [her husband] Aubrey Beauclerk 5th Duke St Albans 1740-1802 (age 26) and Catherine Ponsonby Duchess St Albans (age 24). He a great x 2 grandson of King Charles II of England Scotland and Ireland.
Around 1768 [her daughter] Catherine Elizabeth Beauclerk was born to [her husband] Aubrey Beauclerk 5th Duke St Albans 1740-1802 (age 27) and Catherine Ponsonby Duchess St Albans (age 25). She a great x 2 granddaughter of King Charles II of England Scotland and Ireland.
On 23 May 1771 [her son] Amelius Beauclerk was born to [her husband] Aubrey Beauclerk 5th Duke St Albans 1740-1802 (age 30) and Catherine Ponsonby Duchess St Albans (age 28). He a great x 2 grandson of King Charles II of England Scotland and Ireland.
On 08 May 1773 [her son] Frederick Beauclerk was born to [her husband] Aubrey Beauclerk 5th Duke St Albans 1740-1802 (age 32) and Catherine Ponsonby Duchess St Albans (age 30). He a great x 2 grandson of King Charles II of England Scotland and Ireland.
Around 1775 [her daughter] Caroline Beauclerk was born to [her husband] Aubrey Beauclerk 5th Duke St Albans 1740-1802 (age 34) and Catherine Ponsonby Duchess St Albans (age 32). She a great x 2 granddaughter of King Charles II of England Scotland and Ireland.
In 1776 [her daughter] Georgiana Beauclerk was born to [her husband] Aubrey Beauclerk 5th Duke St Albans 1740-1802 (age 35) and Catherine Ponsonby Duchess St Albans (age 33). She a great x 2 granddaughter of King Charles II of England Scotland and Ireland.
On 10 Feb 1787 George Beauclerk 4th Duke St Albans 1758-1787 (age 28) died unmarried and without issue. His first cousin once removed [her husband] Aubrey Beauclerk 5th Duke St Albans 1740-1802 (age 46) succeeded 5th Duke St Albans, 5th Earl Burford, 5th Baron Heddington. Catherine Ponsonby Duchess St Albans (age 44) by marriage Duchess St Albans.
On 09 Jul 1788 [her son] Aubrey Beauclerk 6th Duke St Albans (age 22) and [her daughter-in-law] Jane Moses (age 20) were married. He the son of Aubrey Beauclerk 5th Duke St Albans 1740-1802 (age 48) and Catherine Ponsonby Duchess St Albans 1742-1789 (age 45). He a great x 2 grandson of King Charles II of England Scotland and Ireland.
On 04 Sep 1789 Catherine Ponsonby Duchess St Albans (age 46) died.
On 09 Feb 1802 [her former husband] Aubrey Beauclerk 5th Duke St Albans 1740-1802 (age 61) died. He was buried at Hanworth. His son [her son] Aubrey Beauclerk 6th Duke St Albans (age 36) succeeded 6th Duke St Albans, 6th Earl Burford, 6th Baron Heddington.
Paternal Family Tree: Ponsonby
Maternal Family Tree: Catherine Hoskyns Duchess Devonshire 1698-1777
Kings Wessex: Great x 21 Grand Daughter of King Edmund "Ironside" I of England
Kings Gwynedd: Great x 18 Grand Daughter of Owain "Great" King Gwynedd 1100-1170
Kings Seisyllwg: Great x 23 Grand Daughter of Hywel "Dda aka Good" King Seisyllwg King Deheubarth
Kings Powys: Great x 19 Grand Daughter of Maredudd ap Bleddyn King Powys 1047-1132
Kings England: Great x 12 Grand Daughter of King Henry IV of England
Kings Scotland: Great x 16 Grand Daughter of Robert "The Bruce" I King Scotland
Kings Franks: Great x 17 Grand Daughter of Louis VII King Franks
Kings France: Great x 14 Grand Daughter of Philip "Bold" III King France
Great x 2 Grandfather: John Ponsonby
Great x 1 Grandfather: William Ponsonby 1st Viscount Duncannon 10 x Great Grand Son of King Edward "Longshanks" I of England
Great x 4 Grandfather: Thomas Folliott of Pirton Court
Great x 3 Grandfather: Henry Folliott 1st Baron Folliott 8 x Great Grand Son of King Edward "Longshanks" I of England
Great x 4 Grandmother: Katherine Lygon
7 x Great Grand Daughter of King Edward "Longshanks" I of England
Great x 2 Grandmother: Elizabeth Folliot 9 x Great Grand Daughter of King Edward "Longshanks" I of England
Great x 4 Grandfather: William Strode of Stoke under Hampden
Great x 3 Grandmother: Anne Strode Countess Roscommon
GrandFather: Brabazon Ponsonby 1st Earl Bessborough 1679-1758 11 x Great Grand Son of King Edward "Longshanks" I of England
Great x 4 Grandfather: Garret Moore 1st Viscount Moore of Drogheda
Great x 3 Grandfather: Charles Moore 2nd Viscount Moore of Drogheda
Great x 4 Grandmother: Mary Colley Viscountess Moore and Wilmot
Great x 2 Grandfather: Randle Moore
Great x 4 Grandfather: Adam Loftus 1st Viscount Loftus
Great x 3 Grandmother: Alice Loftus Viscountess Moore
Great x 1 Grandmother: Mary Moore
Father: William Ponsonby 2nd Earl Bessborough 12 x Great Grand Son of King Edward "Longshanks" I of England
Great x 2 Grandfather: Archbishop James Margetson
Great x 1 Grandfather: John Margetson
Great x 2 Grandmother: Anne Bonnett
GrandMother: Sarah Margetson 13 x Great Grand Daughter of King Edward "Longshanks" I of England
Great x 4 Grandfather: James Caulfeild
Great x 3 Grandfather: William Caulfeild 2nd Baron Caulfeild
Great x 2 Grandfather: William Caulfeild 1st Viscount Charlemont 11 x Great Grand Son of King Edward "Longshanks" I of England
Great x 4 Grandfather: John King
Great x 3 Grandmother: Mary King 10 x Great Grand Daughter of King Edward "Longshanks" I of England
Great x 4 Grandmother: Catherine Drury 9 x Great Grand Daughter of King Edward "Longshanks" I of England
Great x 1 Grandmother: Alice Caulfeild Baroness Carpenter 12 x Great Grand Daughter of King Edward "Longshanks" I of England
Great x 4 Grandfather: Garret Moore 1st Viscount Moore of Drogheda
Great x 3 Grandfather: Charles Moore 2nd Viscount Moore of Drogheda
Great x 4 Grandmother: Mary Colley Viscountess Moore and Wilmot
Great x 2 Grandmother: Sarah Moore Viscountess Charlemont
Great x 4 Grandfather: Adam Loftus 1st Viscount Loftus
Great x 3 Grandmother: Alice Loftus Viscountess Moore
Catherine Ponsonby Duchess St Albans 1742-1789 12 x Great Grand Daughter of Henry IV King England
Great x 4 Grandfather: William Cavendish 2nd Earl Devonshire 9 x Great Grand Son of King Edward "Longshanks" I of England
Great x 3 Grandfather: William Cavendish 3rd Earl Devonshire 10 x Great Grand Son of King Edward "Longshanks" I of England
Great x 4 Grandmother: Christian Bruce Countess Devonshire
Great x 2 Grandfather: William Cavendish 1st Duke Devonshire 9 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: William Cecil 2nd Earl Salisbury
7 x Great Grand Son of King Edward III of England
Great x 3 Grandmother: Elizabeth Cecil Countess Devonshire 1619-1689 8 x Great Grand Daughter of King Edward III of England
Great x 4 Grandmother: Catherine Howard Countess Salisbury
7 x Great Grand Daughter of King Edward III of England
Great x 1 Grandfather: William Cavendish 2nd Duke Devonshire 10 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: Thomas Butler Viscount Thurles
10 x Great Grand Son of King Edward "Longshanks" I of England
Great x 3 Grandfather: James Butler 1st Duke Ormonde 9 x Great Grand Son of King Edward III of England
Great x 4 Grandmother: Elizabeth Poyntz
8 x Great Grand Daughter of King Edward III of England
Great x 2 Grandmother: Mary Butler Duchess Devonshire 10 x Great Grand Daughter of King Edward III of England
Great x 4 Grandfather: Richard Preston 1st Earl Desmond
Great x 3 Grandmother: Elizabeth Preston Duchess Ormonde 9 x Great Grand Daughter of King Edward III of England
Great x 4 Grandmother: Elizabeth Butler 8 x Great Grand Daughter of King Edward III of England
GrandFather: William Cavendish 3rd Duke Devonshire 10 x Great Grand Son of Henry IV King England
Great x 4 Grandfather: Francis Russell 4th Earl Bedford
10 x Great Grand Son of King John "Lackland" of England
Great x 3 Grandfather: William Russell 1st Duke Bedford 9 x Great Grand Son of King Edward III of England
Great x 4 Grandmother: Catherine Brydges Countess Bedford 8 x Great Grand Daughter of King Edward III of England
Great x 2 Grandfather: William Russell 10 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: Robert Carr 1st Earl Somerset
13 x Great Grand Son of King John "Lackland" of England
Great x 3 Grandmother: Anne Carr Countess of Bedford 9 x Great Grand Daughter of King Edward III of England
Great x 4 Grandmother: Frances Howard Countess Essex and Somerset 8 x Great Grand Daughter of King Edward III of England
Great x 1 Grandmother: Rachel Russell Duchess Devonshire 1674-1725 9 x Great Grand Daughter of Henry IV King England
Great x 4 Grandfather: Henry Wriothesley 3rd Earl of Southampton
7 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: Thomas Wriothesley 4th Earl of Southampton 2nd Earl Chichester 7 x Great Grand Son of Henry IV King England
Great x 4 Grandmother: Elizabeth Vernon Countess Southampton 1572-1655
6 x Great Grand Daughter of Henry IV King England
Great x 2 Grandmother: Rachel Wriothesley 8 x Great Grand Daughter of Henry IV King England
Mother: Caroline Cavendish Countess Bessborough 1719-1760 11 x Great Grand Daughter of Henry IV King England