On 31 Aug 1713 [her father] Edward Harley 2nd Earl of Oxford and Earl Mortimer (age 24) and [her mother] Henrietta Cavendish Holles Countess of Oxford and Mortimer 1694-1755 (age 19) were married. She the daughter of John Holles 1st Duke Newcastle upon Tyne and Margaret Cavendish Duchess Newcastle upon Tyne 1661-1716 (age 51). He the son of Robert Harley 1st Earl of Oxford and Earl Mortimer (age 51) and Elizabeth Foley Countess of Oxford and Mortimer.
On 11 Feb 1715 Margaret Cavendish Harley 2nd Duchess Portland was born to Edward Harley 2nd Earl of Oxford and Earl Mortimer (age 25) and Henrietta Cavendish Holles Countess of Oxford and Mortimer 1694-1755 (age 21).
On 21 May 1724 [her grandfather] Robert Harley 1st Earl of Oxford and Earl Mortimer (age 62) died at Albermarle Street. His son [her father] Edward Harley 2nd Earl of Oxford and Earl Mortimer (age 34) succeeded 2nd Earl of Oxford and Earl Mortimer. [her mother] Henrietta Cavendish Holles Countess of Oxford and Mortimer 1694-1755 (age 30) by marriage Countess of Oxford and Countess Mortimer.
On 04 Jul 1726 Henry Bentinck 1st Duke Portland 1682-1726 (age 44) died in Spanish Town Jamaica. His body was returned to England. On 03 Nov 1726 he was buried in the Duke of Ormonde Vault, King Henry VII Chapel, Westminster Abbey. His son [her future husband] William Bentinck 2nd Duke Portland 1709-1762 (age 17) succeeded 2nd Duke Portland, 3rd Earl of Portland.
On 11 Jun 1734 William Bentinck 2nd Duke Portland 1709-1762 (age 25) and Margaret Cavendish Harley 2nd Duchess Portland (age 19) were married at St Peter aka Oxford Chapel Vere Street Marylebone [Map]. She by marriage Duchess Portland. She the daughter of Edward Harley 2nd Earl of Oxford and Earl Mortimer (age 45) and Henrietta Cavendish Holles Countess of Oxford and Mortimer 1694-1755 (age 40). He the son of Henry Bentinck 1st Duke Portland 1682-1726 and Elizabeth Noel Duchess Portland 1688-1737 (age 46).
On 27 Jun 1735 [her daughter] Elizabeth Bentinck Marchioness Bath 1735-1825 was born to [her husband] William Bentinck 2nd Duke Portland 1709-1762 (age 26) and Margaret Cavendish Harley 2nd Duchess Portland (age 20) at Welbeck Abbey [Map].
On 08 Feb 1737 [her daughter] Henrietta Bentinck Countess Stamford and Warrington 1737-1827 was born to [her husband] William Bentinck 2nd Duke Portland 1709-1762 (age 27) and Margaret Cavendish Harley 2nd Duchess Portland (age 21) at Welbeck Abbey [Map].
On 14 Apr 1738 [her son] William Cavendish-Bentinck 3rd Duke Portland was born to [her husband] William Bentinck 2nd Duke Portland 1709-1762 (age 29) and Margaret Cavendish Harley 2nd Duchess Portland (age 23) at Welbeck Abbey [Map].
On 26 Jul 1739 [her daughter] Margaret Cavendish-Bentinck was born to [her husband] William Bentinck 2nd Duke Portland 1709-1762 (age 30) and Margaret Cavendish Harley 2nd Duchess Portland (age 24) at Welbeck Abbey [Map].
On 08 Nov 1739 George Henry Monck and [her sister-in-law] Isabella Cavendish-Bentinck were married. She the daughter of Henry Bentinck 1st Duke Portland 1682-1726 and Elizabeth Noel Duchess Portland 1688-1737.
On 09 Apr 1741 [her daughter] Frances Cavendish-Bentinck was born to [her husband] William Bentinck 2nd Duke Portland 1709-1762 (age 32) and Margaret Cavendish Harley 2nd Duchess Portland (age 26) at Welbeck Abbey [Map].
On 16 Jun 1741 [her father] Edward Harley 2nd Earl of Oxford and Earl Mortimer (age 52) died. His half first cousin Edward Harley 3rd Earl of Oxford and Earl Mortimer 1699-1755 (age 42) succeeded 3rd Earl of Oxford and Earl Mortimer. Martha Morgan Countess of Oxford and Mortimer 1699-1744 (age 42) by marriage Countess of Oxford and Countess Mortimer.
In Mar 1743 [her daughter] Frances Cavendish-Bentinck (age 1) died.
On 03 Mar 1744 [her son] Edward Charles Cavendish-Bentinck was born to [her husband] William Bentinck 2nd Duke Portland 1709-1762 (age 35) and Margaret Cavendish Harley 2nd Duchess Portland (age 29) at Welbeck Abbey [Map].
On 09 Dec 1755 [her mother] Henrietta Cavendish Holles Countess of Oxford and Mortimer 1694-1755 (age 61) died.
On 28 Apr 1756 [her daughter] Margaret Cavendish-Bentinck (age 16) died.
In 1759 [her son-in-law] Thomas Thynne 1st Marquess of Bath (age 24) and [her daughter] Elizabeth Bentinck Marchioness Bath 1735-1825 (age 23) were married. She by marriage Viscountess Weymouth. She the daughter of William Bentinck 2nd Duke Portland 1709-1762 (age 49) and Margaret Cavendish Harley 2nd Duchess Portland 1715-1785 (age 43). They were third cousins.
On 01 May 1762 [her husband] William Bentinck 2nd Duke Portland 1709-1762 (age 53) died. His son [her son] William Cavendish-Bentinck 3rd Duke Portland (age 24) succeeded 3rd Duke Portland, 4th Earl of Portland.
On 28 May 1763 [her son-in-law] George Grey 5th Earl Stamford 1st Earl Warrington (age 25) and [her daughter] Henrietta Bentinck Countess Stamford and Warrington 1737-1827 (age 26) were married. She by marriage Countess Stamford. She the daughter of William Bentinck 2nd Duke Portland 1709-1762 and Margaret Cavendish Harley 2nd Duchess Portland 1715-1785 (age 48). He the son of Henry Grey 4th Earl Stamford (age 47) and Mary Booth Countess Stamford (age 59).
On 08 Nov 1766 [her son] William Cavendish-Bentinck 3rd Duke Portland (age 28) and [her daughter-in-law] Dorothy Cavendish 3rd Duchess Portland 1750-1794 (age 16) were married. She by marriage Duchess Portland. She the daughter of William Cavendish 4th Duke Devonshire and Charlotte Elizabeth Boyle Marchioness Hartington. He the son of William Bentinck 2nd Duke Portland 1709-1762 and Margaret Cavendish Harley 2nd Duchess Portland 1715-1785 (age 51). They were half fourth cousins.
In 1783 [her former sister-in-law] Isabella Cavendish-Bentinck died.
On 17 Jul 1785 Margaret Cavendish Harley 2nd Duchess Portland (age 70) died.
Paternal Family Tree: Harley
Maternal Family Tree: Eleanor Gifford 1575
Kings Wessex: Great x 20 Grand Daughter of King Edmund "Ironside" I of England
Kings Gwynedd: Great x 16 Grand Daughter of Owain "Great" King Gwynedd 1100-1170
Kings Seisyllwg: Great x 22 Grand Daughter of Hywel "Dda aka Good" King Seisyllwg King Deheubarth
Kings Powys: Great x 17 Grand Daughter of Maredudd ap Bleddyn King Powys 1047-1132
Kings England: Great x 8 Grand Daughter of King Edward IV of England
Kings Scotland: Great x 15 Grand Daughter of William "Lion" I King Scotland
Kings Franks: Great x 16 Grand Daughter of Louis VII King Franks
Kings France: Great x 13 Grand Daughter of Philip "The Fair" IV King France
Great x 4 Grandfather: John Harley of Brampton Bryan
Great x 3 Grandfather: Thomas Harley
Great x 2 Grandfather: Robert Harley 10 x Great Grand Son of King John "Lackland" of England
Great x 4 Grandfather: Andrew Corbet 8 x Great Grand Son of King John "Lackland" of England
Great x 3 Grandmother: Margaret Corbet 9 x Great Grand Daughter of King John "Lackland" of England
Great x 1 Grandfather: Edward Harley 9 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: John Conway of Arrow
Great x 3 Grandfather: Edward Conway 1st Viscount Conway 7 x Great Grand Son of King Edward III of England
Great x 4 Grandmother: Helen Greville
6 x Great Grand Daughter of King Edward III of England
Great x 2 Grandmother: Brilliana Conway 8 x Great Grand Daughter of King Edward III of England
GrandFather: Robert Harley 1st Earl of Oxford and Earl Mortimer 10 x Great Grand Son of King Edward III of England
Father: Edward Harley 2nd Earl of Oxford and Earl Mortimer 11 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: Richard Foley
Great x 3 Grandfather: Richard Foley
Great x 2 Grandfather: Thomas Foley
Great x 4 Grandfather: William Brindley of Willenhal
Great x 3 Grandmother: Alice Brindley
Great x 1 Grandfather: Thomas Foley
GrandMother: Elizabeth Foley Countess of Oxford and Mortimer
Margaret Cavendish Harley 2nd Duchess Portland 1715-1785 8 x Great Grand Daughter of King Edward IV of England
Great x 4 Grandfather: Denzil Holles
Great x 3 Grandfather: John Holles 1st Earl de Clare 7 x Great Grand Son of King Edward III of England
Great x 4 Grandmother: Eleanor Sheffield 6 x Great Grand Daughter of King Edward III of England
Great x 2 Grandfather: John Holles 2nd Earl de Clare 1595-1666 7 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: Thomas Stanhope
5 x Great Grand Son of King Edward III of England
Great x 3 Grandmother: Anne Stanhope Countess de Clare 1576-1651 6 x Great Grand Daughter of King Edward III of England
Great x 4 Grandmother: Margaret Port
Great x 1 Grandfather: Gilbert Holles 3rd Earl de Clare 1633-1689 8 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: Geoffrey Vere
6 x Great Grand Son of King Edward "Longshanks" I of England
Great x 3 Grandfather: Horace de Vere 1st Baron Vere 7 x Great Grand Son of King Edward "Longshanks" I of England
Great x 4 Grandmother: Elizabeth Hardkyn
Great x 2 Grandmother: Elizabeth Vere Countess Clare 8 x Great Grand Daughter of King Edward "Longshanks" I of England
Great x 4 Grandfather: John Tracy
Great x 3 Grandmother: Mary Tracy Baroness Spencer Tilbury
GrandFather: John Holles 1st Duke Newcastle upon Tyne 9 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: Henry Pierrepont
10 x Great Grand Son of King John "Lackland" of England
Great x 3 Grandfather: Robert Pierrepont 1st Earl Kingston 9 x Great Grand Son of King Edward "Longshanks" I of England
Great x 4 Grandmother: Frances Cavendish 8 x Great Grand Daughter of King Edward "Longshanks" I of England
Great x 2 Grandfather: William Pierrepont of Thoresby 8 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: Henry Talbot
6 x Great Grand Son of King Edward III of England
Great x 3 Grandmother: Gertrude Talbot Baroness Pierrepont Holme Pierrepoint 7 x Great Grand Daughter of King Edward III of England
Great x 4 Grandmother: Elizabeth Rayner
Great x 1 Grandmother: Grace Pierrepont Countess de Clare 1633-1702 9 x Great Grand Daughter of King Edward III of England
Great x 4 Grandfather: John Harries of Cruckton in Shropshire
Great x 3 Grandfather: Thomas Harries aka Harris 1st Baronet
Great x 4 Grandmother: Eleanor Prowde
Great x 2 Grandmother: Elizabeth Harries aka Harris
Great x 4 Grandfather: Roger Gifford Physican
Great x 3 Grandmother: Eleanor Gifford
Mother: Henrietta Cavendish Holles Countess of Oxford and Mortimer 1694-1755 7 x Great Grand Daughter of King Edward IV of England
Great x 4 Grandfather: William Cavendish 7 x Great Grand Son of King Edward "Longshanks" I of England
Great x 3 Grandfather: Charles Cavendish 8 x Great Grand Son of King Edward "Longshanks" I of England
Great x 4 Grandmother: Bess of Hardwick Countess Shrewsbury and Waterford
Great x 2 Grandfather: William Cavendish 1st Duke Newcastle upon Tyne 4 x Great Grand Son of King Edward IV of England
Great x 4 Grandfather: Cuthbert Ogle 7th Baron Ogle 2 x Great Grand Son of King Edward IV of England
Great x 3 Grandmother: Catherine Ogle 8th Baroness Ogle 3 x Great Grand Daughter of King Edward IV of England
Great x 4 Grandmother: Catherine Carnaby Baroness Ogle 7 x Great Grand Daughter of King Edward III of England
Great x 1 Grandfather: Henry Cavendish 2nd Duke Newcastle upon Tyne 5 x Great Grand Son of King Edward IV of England
Great x 4 Grandfather: William Bassett
13 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 3 Grandfather: William Bassett 11 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandmother: Elizabeth Fitzherbert
10 x Great Grand Daughter of King Henry "Curtmantle" II of England
Great x 2 Grandmother: Elizabeth Bassett Countess Newcastle upon Tyne 12 x Great Grand Daughter of King Henry "Curtmantle" II of England
GrandMother: Margaret Cavendish Duchess Newcastle upon Tyne 1661-1716 6 x Great Grand Daughter of King Edward IV of England
Great x 4 Grandfather: Henry Pierrepont 10 x Great Grand Son of King John "Lackland" of England
Great x 3 Grandfather: Robert Pierrepont 1st Earl Kingston 9 x Great Grand Son of King Edward "Longshanks" I of England
Great x 4 Grandmother: Frances Cavendish 8 x Great Grand Daughter of King Edward "Longshanks" I of England
Great x 2 Grandfather: William Pierrepont of Thoresby 8 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: Henry Talbot 6 x Great Grand Son of King Edward III of England
Great x 3 Grandmother: Gertrude Talbot Baroness Pierrepont Holme Pierrepoint 7 x Great Grand Daughter of King Edward III of England
Great x 4 Grandmother: Elizabeth Rayner
Great x 1 Grandmother: Frances Pierrepont Duchess Newcastle upon Tyne 1630-1695 9 x Great Grand Daughter of King Edward III of England
Great x 4 Grandfather: John Harries of Cruckton in Shropshire
Great x 3 Grandfather: Thomas Harries aka Harris 1st Baronet
Great x 4 Grandmother: Eleanor Prowde
Great x 2 Grandmother: Elizabeth Harries aka Harris
Great x 4 Grandfather: Roger Gifford Physican
Great x 3 Grandmother: Eleanor Gifford