On 11 Aug 1746 [her father] William Stanhope 2nd Earl of Harrington 1719-1779 (age 26) and [her mother] Caroline Fitzroy Countess Harrington (age 24) were married. She the daughter of Charles Fitzroy 2nd Duke Grafton (age 62) and Henrietta Somerset Duchess Grafton 1690-1726. He the son of William Stanhope 1st Earl of Harrington 1683-1756 (age 63) and Anne Griffith. She a great granddaughter of King Charles II of England Scotland and Ireland. 
Around 1748 Isabella Stanhope Countess Sefton was born to William Stanhope 2nd Earl of Harrington 1719-1779 (age 28) and Caroline Fitzroy Countess Harrington (age 25). She a great x 2 granddaughter of King Charles II of England Scotland and Ireland.
In 1755 Walter Smythe (age 34) and [her future sister-in-law] Mary Ann Errington (age 20) were married.
On 08 Dec 1756 [her grandfather] William Stanhope 1st Earl of Harrington 1683-1756 (age 73) died. His son [her father] William Stanhope 2nd Earl of Harrington 1719-1779 (age 36) succeeded 2nd Earl Harrington, 2nd Viscount Petersham, 2nd Baron Harrington. [her mother] Caroline Fitzroy Countess Harrington (age 34) by marriage Countess Harrington.
On 30 Mar 1759 William Molyneux 7th Viscount Molyneux (age 74) died. His nephew [her future husband] Charles Molyneux 1st Earl Sefton 1748-1795 (age 10) succeeded 8th Viscount Molyneux, 9th Baronet Molyneux of Sefton.
On 27 Nov 1768 Charles Molyneux 1st Earl Sefton 1748-1795 (age 20) and Isabella Stanhope Countess Sefton (age 20) were married. She by marriage Viscountess Molyneux. She the daughter of William Stanhope 2nd Earl of Harrington 1719-1779 (age 48) and Caroline Fitzroy Countess Harrington (age 46). She a great x 2 granddaughter of King Charles II of England Scotland and Ireland.
On 30 Nov 1771 [her husband] Charles Molyneux 1st Earl Sefton 1748-1795 (age 23) was created 1st Earl Sefton for his having conformed to the Church of England. Isabella Stanhope Countess Sefton (age 23) by marriage Countess Sefton.
On 18 Sep 1772 [her son] William "Lord Dashalong" Molyneux 2nd Earl Sefton 1772-1838 was born to [her husband] Charles Molyneux 1st Earl Sefton 1748-1795 (age 23) and Isabella Stanhope Countess Sefton (age 24). He a great x 3 grandson of King Charles II of England Scotland and Ireland.
On 01 Apr 1779 [her father] William Stanhope 2nd Earl of Harrington 1719-1779 (age 59) died. His son [her brother] Charles Stanhope 3rd Earl of Harrington 1753-1829 (age 26) succeeded 3rd Earl Harrington, 3rd Viscount Petersham, 3rd Baron Harrington. Jane Fleming Countess Harrington (age 23) by marriage Countess Harrington.
On 26 Jun 1784 [her mother] Caroline Fitzroy Countess Harrington (age 62) died.
In 1792 [her son] William "Lord Dashalong" Molyneux 2nd Earl Sefton 1772-1838 (age 19) and [her daughter-in-law] Maria Margaret Craven Countess Sefton were married. She the daughter of William Craven 6th Baron Craven and Elizabeth Berkeley Margrave Brandenburg Ansbach 1750-1828 (age 41). He the son of Charles Molyneux 1st Earl Sefton 1748-1795 (age 43) and Isabella Stanhope Countess Sefton 1748-1819 (age 44). They were half fourth cousins. He a great x 3 grandson of King Charles II of England Scotland and Ireland. She a great x 3 granddaughter of King Charles II of England Scotland and Ireland. 
On 31 Jan 1795 [her husband] Charles Molyneux 1st Earl Sefton 1748-1795 (age 46) died. On 31 Jan 1795 His son [her son] William "Lord Dashalong" Molyneux 2nd Earl Sefton 1772-1838 (age 22) succeeded 2nd Earl Sefton, 9th Viscount Molyneux, 10th Baronet Molyneux of Sefton. [her daughter-in-law] Maria Margaret Craven Countess Sefton by marriage Countess Sefton.
Around 1800 [her former sister-in-law] Mary Ann Errington (age 65) died.
On 29 Jan 1819 Isabella Stanhope Countess Sefton (age 71) died.
Paternal Family Tree: Stanhope
Maternal Family Tree: Rebecca Child Marchioness Worcester 1666-1712
Descendants Family Trees:
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 24 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 2 Grand Daughter of King Charles II of England Scotland and Ireland
Kings Scotland: Great x 14 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 4 Grand Daughter of Henry IV King France
Great x 4 Grandfather: John Stanhope 6 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: John Stanhope 7 x Great Grand Son of King Edward III of England
Great x 4 Grandmother: Catherine Trentham
Great x 2 Grandfather: John Stanhope 8 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: John Radclyffe of Ordsall
Great x 3 Grandmother: Mary Radclyffe Lady Gell
Great x 1 Grandfather: John Stanhope 8 x Great Grand Son of Henry IV King England
Great x 4 Grandfather: John Curzon 5 x Great Grand Son of Henry IV King England
Great x 3 Grandfather: John Curzon 1st Baronet 6 x Great Grand Son of Henry IV King England
Great x 4 Grandmother: Millicent Sacheverell 12 x Great Grand Daughter of King Henry "Curtmantle" II of England
Great x 2 Grandmother: Jane Curzon 7 x Great Grand Daughter of Henry IV King England
Great x 4 Grandfather: Thomas Crew
Great x 3 Grandmother: Patience Crewe Baroness Curzon
Great x 4 Grandmother: Temperance Bray
GrandFather: William Stanhope 1st Earl of Harrington 1683-1756 9 x Great Grand Son of Henry IV King England
Father: William Stanhope 2nd Earl of Harrington 1719-1779 10 x Great Grand Son of Henry IV King England
Great x 1 Grandfather: Colonel Edward Griffith
GrandMother: Anne Griffith
Isabella Stanhope Countess Sefton 1748-1819 2 x Great Grand Daughter of King Charles II of England Scotland and Ireland
Great x 4 Grandfather: King James I of England and Ireland and VI of Scotland 2 x Great Grand Son of King Henry VII of England and Ireland
Great x 3 Grandfather: King Charles I of England, Scotland and Ireland
Son of King James I of England and Ireland and VI of Scotland
Great x 4 Grandmother: Anne of Denmark Queen Consort Scotland England and Ireland
12 x Great Grand Daughter of King Henry "Curtmantle" II of England
Great x 2 Grandfather: King Charles II of England Scotland and Ireland Son of King Charles I of England, Scotland and Ireland
Great x 4 Grandfather: Henry IV King France
7 x Great Grand Son of King Edward III of England
Great x 3 Grandmother: Henrietta Maria Bourbon Queen Consort England 7 x Great Grand Daughter of King Edward III of England
Great x 4 Grandmother: Marie de Medici Queen Consort France 6 x Great Grand Daughter of King Edward III of England
Great x 1 Grandfather: Henry Fitzroy 1st Duke Grafton Son of King Charles II of England Scotland and Ireland
Great x 4 Grandfather: Edward Villiers
Great x 3 Grandfather: William Villiers 2nd Viscount Grandison 9 x Great Grand Son of King Edward III of England
Great x 4 Grandmother: Barbara St John
8 x Great Grand Daughter of King Edward III of England
Great x 2 Grandmother: Barbara Villiers 1st Duchess of Cleveland 10 x Great Grand Daughter of King Edward III of England
GrandFather: Charles Fitzroy 2nd Duke Grafton Grand Son of King Charles II of England Scotland and Ireland
Great x 3 Grandfather: John Bennet
Great x 2 Grandfather: Henry Bennet 1st Earl Arlington 10 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: John Crofts 8 x Great Grand Son of King Edward III of England
Great x 3 Grandmother: Dorothy Crofts 9 x Great Grand Daughter of King Edward III of England
Great x 4 Grandmother: Mary Shirley
10 x Great Grand Daughter of King Henry III of England
Great x 1 Grandmother: Isabella Bennet Duchess Grafton 11 x Great Grand Daughter of King Edward III of England
Great x 4 Grandfather: Prince Maurice I of Orange 12 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 3 Grandfather: Louis Nassau Beverweert 13 x Great Grand Son of King Henry "Curtmantle" II of England
Great x 4 Grandmother: Margaretha van Mechelen
Great x 2 Grandmother: Elisabeth Nassau Beverweert Countess Arlington 14 x Great Grand Daughter of King Henry "Curtmantle" II of England
Mother: Caroline Fitzroy Countess Harrington Great Grand Daughter of King Charles II of England Scotland and Ireland
Great x 4 Grandfather: Henry Somerset 1st Marquess Worcester 1577-1646 7 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: Edward Somerset 2nd Marquess Worcester 8 x Great Grand Son of King Edward III of England
Great x 4 Grandmother: Anne Russell 2nd Marchioness Worcester 1578-1639
10 x Great Grand Daughter of King John "Lackland" of England
Great x 2 Grandfather: Henry Somerset 1st Duke Beaufort 9 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: Robert Dormer 1st Earl Carnarvon 1610-1643
8 x Great Grand Son of King Edward III of England
Great x 3 Grandmother: Elizabeth Dormer 9 x Great Grand Daughter of King Edward III of England
Great x 4 Grandmother: Anne Sophia Herbert Countess Carnarvon
8 x Great Grand Daughter of King Edward III of England
Great x 1 Grandfather: Charles Somerset Marquess Worcester 10 x Great Grand Son of King Edward III of England
Great x 4 Grandfather: Henry Capell 7 x Great Grand Son of King Edward III of England
Great x 3 Grandfather: Arthur Capell 1st Baron Capell Hadham 8 x Great Grand Son of King Edward III of England
Great x 4 Grandmother: Theodosia Montagu
9 x Great Grand Daughter of King Edward "Longshanks" I of England
Great x 2 Grandmother: Mary Capell Duchess Beaufort 9 x Great Grand Daughter of King Edward III of England
Great x 4 Grandfather: Charles Morrison
7 x Great Grand Son of King Edward III of England
Great x 3 Grandmother: Elizabeth Morrison Baroness Capell Hadham 8 x Great Grand Daughter of King Edward III of England
Great x 4 Grandmother: Mary Hicks Lady Cooper
GrandMother: Henrietta Somerset Duchess Grafton 1690-1726 11 x Great Grand Daughter of King Edward III of England
Great x 3 Grandfather: Richard Child
Great x 2 Grandfather: Josiah Child
Great x 3 Grandmother: Elizabeth Roycroft
Great x 1 Grandmother: Rebecca Child Marchioness Worcester
