Emilia St George Duchess Leinster was born to St George Ussher aka St George 1st Baron Saint George.
On 19 Apr 1763 [her father] St George Ussher aka St George 1st Baron Saint George (age 48) was created 1st Baron Saint George of Hatley St George in the Peerage of Ireland. His grandfather George St George 1st Baron St George had been the first and last Baron St George albeit in the Peerage of England.
On 19 Nov 1773 James Fitzgerald 1st Duke Leinster 1722-1773 (age 51) died. His son [her future husband] William Robert Fitzgerald 2nd Duke Leinster 1749-1804 (age 24) succeeded 2nd Duke Leinster.
On 02 Jan 1775 [her father] St George Ussher aka St George 1st Baron Saint George (age 60) died. Baron Saint George of Hatley St George extinct.
On 04 Nov 1775 or 07 Nov 1775 William Robert Fitzgerald 2nd Duke Leinster 1749-1804 (age 26) and Emilia St George Duchess Leinster were married. She by marriage Duchess Leinster. He the son of James Fitzgerald 1st Duke Leinster 1722-1773 and Emilia Mary Lennox Duchess Leinster 1731-1814 (age 44). He a great x 2 grandson of King Charles II of England Scotland and Ireland. 
In 1776 [her sister-in-law] Louisa Fitzgerald (age 4) died.
On 06 May 1777 [her daughter] Mary Rebecca Fitzgerald was born to [her husband] William Robert Fitzgerald 2nd Duke Leinster 1749-1804 (age 28) and Emilia St George Duchess Leinster. She a great x 3 granddaughter of King Charles II of England Scotland and Ireland.
On 13 May 1778 [her daughter] Emily Elizabeth Fitzgerald was born to [her husband] William Robert Fitzgerald 2nd Duke Leinster 1749-1804 (age 29) and Emilia St George Duchess Leinster. She a great x 3 granddaughter of King Charles II of England Scotland and Ireland.
In 1780 [her daughter] Elizabeth Fitzgerald was born to [her husband] William Robert Fitzgerald 2nd Duke Leinster 1749-1804 (age 30) and Emilia St George Duchess Leinster. She a great x 3 granddaughter of King Charles II of England Scotland and Ireland.
In 1783 [her brother-in-law] George Simon Son Fitzgerald (age 9) died.
On 20 Jun 1783 [her son] George Fitzgerald was born to [her husband] William Robert Fitzgerald 2nd Duke Leinster 1749-1804 (age 34) and Emilia St George Duchess Leinster at Carton, Kildare, County Kildare. He a great x 3 grandson of King Charles II of England Scotland and Ireland.
On 03 Mar 1786 [her daughter] Cecilia Olivia Geraldine Fitzgerald Baroness Foley was born to [her husband] William Robert Fitzgerald 2nd Duke Leinster 1749-1804 (age 36) and Emilia St George Duchess Leinster. She a great x 3 granddaughter of King Charles II of England Scotland and Ireland.
On 09 Sep 1787 [her daughter] Olivia Letitia Catherine Fitzgerald was born to [her husband] William Robert Fitzgerald 2nd Duke Leinster 1749-1804 (age 38) and Emilia St George Duchess Leinster. She a great x 3 granddaughter of King Charles II of England Scotland and Ireland.
In 1788 [her brother-in-law] Gerald Fitzgerald (age 21) drowned.
On 21 or 23 Feb 1789 Joseph Strutt (age 30) and [her sister-in-law] Charlotte Fitzgerald 1st Baroness Rayleigh (age 30) were married. She the daughter of James Fitzgerald 1st Duke Leinster 1722-1773 and Emilia Mary Lennox Duchess Leinster 1731-1814 (age 57). She a great x 2 granddaughter of King Charles II of England Scotland and Ireland.
On 21 Aug 1791 [her son] Augustus Fitzgerald 3rd Duke Leinster 1791-1874 was born to [her husband] William Robert Fitzgerald 2nd Duke Leinster 1749-1804 (age 42) and Emilia St George Duchess Leinster. He a great x 3 grandson of King Charles II of England Scotland and Ireland.
On 04 Jan 1793 [her son] William Charles Fitzgerald was born to [her husband] William Robert Fitzgerald 2nd Duke Leinster 1749-1804 (age 43) and Emilia St George Duchess Leinster. He a great x 3 grandson of King Charles II of England Scotland and Ireland.
In or before 1798. Hugh Douglas Hamilton (age 57). Portrait of Emilia St George Duchess Leinster.
In 1798 Emilia St George Duchess Leinster died.
On 20 Oct 1804 [her former husband] William Robert Fitzgerald 2nd Duke Leinster 1749-1804 (age 55) died at Carton House, Carton, Kildare, County Kildare. His son [her son] Augustus Fitzgerald 3rd Duke Leinster 1791-1874 (age 13) succeeded 3rd Duke Leinster.
Henry Fitzgerald and Charlotte Boyle 20th Baroness Ros Helmsley were married. He the son of James Fitzgerald 1st Duke Leinster 1722-1773 and Emilia Mary Lennox Duchess Leinster 1731-1814. They were third cousin once removed. He a great x 2 grandson of King Charles II of England Scotland and Ireland. 
Maternal Family Tree: Emilia St George Duchess Leinster 1798
GrandFather: John Ussher
Father: St George Ussher aka St George 1st Baron Saint George
Great x 3 Grandfather: George St George
Great x 2 Grandfather: Oliver St George 1st Baronet
Great x 1 Grandfather: George St George 1st Baron St George
Great x 4 Grandfather: Tristram Beresford
Great x 3 Grandfather: Michael Beresford
Great x 2 Grandmother: Olivia Beresford
GrandMother: Mary St George
Great x 4 Grandfather: William Skeffington 1st Baronet
Great x 3 Grandfather: Richard Skeffington
Great x 4 Grandmother: Margaret Dering of Surrenden
Great x 2 Grandfather: John Skeffington 2nd Viscount Massereene
Great x 4 Grandfather: John Newdigate of Arbury in Warwickshire
Great x 3 Grandmother: Anne Newdigate
Great x 1 Grandmother: Margaret Skeffington Lady St George
Great x 3 Grandfather: John Clotworthy 1st Viscount Massereene
Great x 2 Grandmother: Mary Clotworthy
Great x 4 Grandfather: Roger Jones 1st Viscount Ranelagh
Great x 3 Grandmother: Margaret Jones
Great x 4 Grandmother: Frances Moore