Before Jul 1748 [his father] Watkin Williams-Wynn 3rd Baronet (age 56) and Ann Vaughan were married.

In Jul 1748 [his father] Watkin Williams-Wynn 3rd Baronet (age 56) and [his mother] Frances Shackerley Lady Williams-Wynn (age 27) were married. She was his god-daughter. The difference in their ages was 29 years.

On 23 Sep 1749 Watkin Williams-Wynn 4th Baronet was born to Watkin Williams-Wynn 3rd Baronet (age 57) and Frances Shackerley Lady Williams-Wynn (age 28).

On 26 Sep 1749 [his father] Watkin Williams-Wynn 3rd Baronet (age 57) died. His son Watkin Williams-Wynn 4th Baronet succeeded 4th Baronet Williams of Gray's Inn. [his future wife] Henrietta Somerset Lady Williams-Wynn (age 1) by marriage Lady Williams of Gray's Inn.

After 1769. Joshua Reynolds (age 45). Portrait of Watkin Williams-Wynn 4th Baronet (age 19) and [his future wife] Henrietta Somerset Lady Williams-Wynn (age 20). The couple are depicted life-size in matching black and pink Van Dyck costume, and are holding theatrical masks in a curtained architectural setting, beside a massive vase. The picture was presumably begun as a marriage portrait, although it is unlikely to have been completed prior to Lady Henrietta's death on 25 July 1769. Williams-Wynn sat for Reynolds in February 1769, his fiancée in March, and Sir Watkin once again in August. The black costume of the figures suggest that it was completed as a memorial portrait after Henrietta Williams-Wynn's death.

On 13 Apr 1769 Watkin Williams-Wynn 4th Baronet (age 19) and Henrietta Somerset Lady Williams-Wynn (age 20) were married. She died fifteen weeks later. She the daughter of Charles Noel Somerset 4th Duke Beaufort and Elizabeth Berekeley Duchess Beaufort (age 56).

On 25 Jul 1769 [his wife] Henrietta Somerset Lady Williams-Wynn (age 21) died fifteen weeks after she married of unknown causes.

In Dec 1771 Watkin Williams-Wynn 4th Baronet (age 22) and Charlotte Granville Lady Williams-Wynn (age 17) were married. She by marriage Lady Williams of Gray's Inn.

On 25 Oct 1772 [his son] Watkin Williams-Wynn 5th Baronet was born to Watkin Williams-Wynn 4th Baronet (age 23) and [his wife] Charlotte Granville Lady Williams-Wynn (age 18).

In 1775 [his brother-in-law] George Nugent Temple Grenville 1st Marquess Buckingham (age 21) and Mary Elizabeth Nugent Marchioness Buckingham (age 17) were married. She the daughter of Robert Nugent 1st Earl Nugent (age 66) and Elizabeth Drax Countess Berkeley and Nugent (age 55).

On 09 Oct 1775 [his son] Charles Williams-Wynn was born to Watkin Williams-Wynn 4th Baronet (age 26) and [his wife] Charlotte Granville Lady Williams-Wynn (age 21).

On 12 Sep 1779 Richard Grenville-Temple 2nd Earl Temple (age 67) died in a carriage accident without surviving issue. His nephew [his brother-in-law] George Nugent Temple Grenville 1st Marquess Buckingham (age 26) succeeded 3rd Earl Temple, 4th Viscount Cobham.

On 10 May 1782 Hugh Fortescue 1st Earl Fortescue (age 29) and [his sister-in-law] Hester Granville Countess Fortescue (age 16) were married.

On 16 Mar 1783 [his son] Henry Watkin Williams-Wynn was born to Watkin Williams-Wynn 4th Baronet (age 33) and [his wife] Charlotte Granville Lady Williams-Wynn (age 29).

In Dec 1784 [his brother-in-law] George Nugent Temple Grenville 1st Marquess Buckingham (age 31) was created 1st Marquess Buckingham.

On 13 Oct 1788 Robert Nugent 1st Earl Nugent (age 79) died. [his brother-in-law] George Nugent Temple Grenville 1st Marquess Buckingham (age 35) succeeded 2nd Earl Nugent. Viscount Clare, Baron Nugent extinct.

On 24 Jul 1789 Watkin Williams-Wynn 4th Baronet (age 39) died. His son [his son] Watkin Williams-Wynn 5th Baronet (age 16) succeeded 5th Baronet Williams of Gray's Inn.

On 29 Sep 1830 [his former wife] Charlotte Granville Lady Williams-Wynn (age 76) died.

[his daughter] Henrietta Elizabeth Williams-Wynn Baroness Delamere was born to Watkin Williams-Wynn 4th Baronet and Henrietta Somerset Lady Williams-Wynn.