On 26 Apr 1540 [her father] Francis Knollys (age 28) and [her mother] Catherine Carey (age 16) were married. She a great x 5 granddaughter of King Edward III of England.

On 04 Jun 1550 [her future husband] Robert Dudley 1st Earl of Leicester (age 17) and Amy Robsart (age 17) were married at Sheen Palace [Map]. King Edward VI of England and Ireland (age 12) and William Cecil 1st Baron Burghley (age 29) attended. He the son of John Dudley 1st Duke Northumberland (age 46) and Jane Guildford Duchess Northumberland (age 41).

In 1551 Henry Sidney (age 22) and [her future sister-in-law] Mary Dudley (age 21) were married. She the daughter of John Dudley 1st Duke Northumberland (age 47) and Jane Guildford Duchess Northumberland (age 42).

Around 1561 Walter Devereux 1st Earl Essex (age 19) and Lettice Knollys Countess Essex (age 17) were married. She by marriage Viscountess Hereford. They were fourth cousins.

On 21 Sep 1578 Robert Dudley 1st Earl of Leicester (age 46) and Lettice Knollys Countess Essex (age 34) were married secretly much to the anguish of Queen Elizabeth I of England and Ireland (age 45) who developed a deep hatred of Lettice Knollys Countess Essex (age 34). She by marriage Countess of Leicester. Roger North 2nd Baron North (age 48) was present. He the son of John Dudley 1st Duke Northumberland and Jane Guildford Duchess Northumberland.

On 10 Jan 1581 [her son-in-law] Robert Rich 1st Earl Warwick (age 21) and [her daughter] Penelope Devereux Countess Devonshire (age 18) were married. She by marriage Baroness Rich of Leez. She the daughter of Walter Devereux 1st Earl Essex and Lettice Knollys Countess Essex (age 37).

On 17 Jul 1583 [her son-in-law] Thomas Perrot (age 30) and [her daughter] Dorothy Devereux Countess Northumberland (age 19) were married. The marriage took place without the consent of the Queen to whom Dorothy was lady in Waiting for which Thomas was imprisoned in the Fleet Prison [Map]. She the daughter of Walter Devereux 1st Earl Essex and Lettice Knollys Countess Essex (age 39).

In 1589 [her son] Walter Devereux (age 19) and [her daughter-in-law] Margaret Dakins (age 18) were married. He the son of Walter Devereux 1st Earl Essex and Lettice Knollys Countess Essex (age 45).

Around Apr 1589 Christopher Blount (age 24) and Lettice Knollys Countess Essex (age 45) were married. The difference in their ages was 21 years; she, unusually, being older than him.

In 1590 [her son] Robert Devereux 2nd Earl Essex (age 24) and [her daughter-in-law] Frances Walsingham Countess Essex (age 23) were married. She by marriage Countess Essex. He the son of Walter Devereux 1st Earl Essex and Lettice Knollys Countess Essex (age 46).

Around 1591 [her illegitimate step-son] Robert Dudley (age 16) and Margaret Cavendish (age 21) were married. He the illegitmate son of Robert Dudley 1st Earl of Leicester and Douglas Howard Baroness Sheffield (age 49).

In 1594 [her son-in-law] Henry "Wizard Earl" Percy 9th Earl of Northumberland (age 29) and [her daughter] Dorothy Devereux Countess Northumberland (age 30) were married. She the daughter of Walter Devereux 1st Earl Essex and Lettice Knollys Countess Essex (age 50). He the son of Henry Percy 8th Earl of Northumberland and Katherine Neville Countess Northumberland (age 49). They were third cousin once removed.

Around 1596 [her illegitimate step-son] Robert Dudley (age 21) and Alice Leigh 1st Duchess Dudley (age 18) were married. He the illegitmate son of Robert Dudley 1st Earl of Leicester and Douglas Howard Baroness Sheffield (age 54).

In 1605 [her son-in-law] Robert Rich 1st Earl Warwick (age 45) and [her daughter] Penelope Devereux Countess Devonshire (age 41) were divorced.

On 26 Dec 1605 [her son-in-law] Charles Blount 1st Earl Devonshire (age 42) and [her daughter] Penelope Devereux Countess Devonshire (age 42) were married at Wansted House during a service conducted by Archbishop William Laud (age 32) (future). The marriage was regarded as uncanonical and resulted in the disgrace of both parties, who were banished from King James I's court circles. She by marriage Countess Devonshire. She the daughter of Walter Devereux 1st Earl Essex and Lettice Knollys Countess Essex (age 62). They were third cousins.

In 1606 [her illegitimate step-son] Robert Dudley (age 31) and Elizabeth Southwell (age 22) were married at Lyon, France [Map]. Bigamous in his case since his second wife Alice Leigh 1st Duchess Dudley (age 28) was alive. She the daughter of Robert Southwell and Elizabeth Howard Countess Carrick (age 41). He the illegitmate son of Robert Dudley 1st Earl of Leicester and Douglas Howard Baroness Sheffield (age 64). They were first cousin once removed.