Before 1424 [his father] James "Gross" Douglas 7th Earl Douglas 1st Earl Avondale (age 53) and Beatrice Stewart Countess Douglas and Avondale (age 62) were married. She by marriage Countess Douglas, Countess Avondale. She the daughter of Robert Stewart 1st Duke Albany and Margaret Graham Countess Menteith and Fife. He the son of Archibald "Grim" Douglas 3rd Earl Douglas and Joanna Strathearn Countess Douglas. They were half third cousin once removed. She a great x 5 granddaughter of King John "Lackland" of England.

Before 05 Jan 1442 John Neville 1st Baron Neville of Raby (age 32) and [his future wife] Anne Holland Countess Douglas and Avondale were married. She the daughter of John Holland 2nd Duke Exeter (age 46) and Anne Stafford Duchess Exeter. They were second cousins. He a great x 3 grandson of King Edward "Longshanks" I of England. She a great x 2 granddaughter of King Edward III of England.

Before 16 Mar 1450 John Neville and [his future wife] Anne Holland Countess Douglas and Avondale were married. She the daughter of John Holland 2nd Duke Exeter and Anne Stafford Duchess Exeter. He the son of Ralph Neville 2nd Earl of Westmoreland (age 43) and Elizabeth Percy Countess of Westmoreland. They were second cousin once removed. He a great x 3 grandson of King Edward III of England. She a great x 2 granddaughter of King Edward III of England.

Before 22 Feb 1452 [his brother] William Douglas 8th Earl Douglas 2nd Earl Avondale (age 27) and [his future wife] Margaret "Fair Lady of Galloway" Douglas Countess (age 17) were married. She would later marry his younger brother James Douglas 9th Earl Douglas 3rd Earl Avondale (age 26); an example of Married to Two Siblings. She the daughter of Archibald Douglas 2nd Duke Touraine and Euphemia Graham Lady Hamilton (age 44). He the son of James "Gross" Douglas 7th Earl Douglas 1st Earl Avondale and Beatrix Sinclair Countess Douglas and Avondale (age 54). They were first cousin once removed.

Before 1455 James Douglas 9th Earl Douglas 3rd Earl Avondale (age 29) and Margaret "Fair Lady of Galloway" Douglas Countess (age 19) were married. She by marriage Countess Douglas, Countess Avondale. She had previously married his brother William Douglas 8th Earl Douglas 2nd Earl Avondale; an example of Married to Two Siblings. She the daughter of Archibald Douglas 2nd Duke Touraine and Euphemia Graham Lady Hamilton (age 46). He the son of James "Gross" Douglas 7th Earl Douglas 1st Earl Avondale and Beatrix Sinclair Countess Douglas and Avondale (age 56). They were first cousin once removed.

Around 1459 John Stewart 1st Earl Atholl (age 19) and [his wife] Margaret "Fair Lady of Galloway" Douglas Countess (age 24) were married. She by marriage Countess Atholl. She the daughter of Archibald Douglas 2nd Duke Touraine and Euphemia Graham Lady Hamilton (age 51). He the son of James "Black Knight of Lorn" Stewart and Joan Beaufort Queen Consort Scotland. He a great x 2 grandson of King Edward III of England.

After 1463 James Douglas 9th Earl Douglas 3rd Earl Avondale (age 37) and Anne Holland Countess Douglas and Avondale were married. She by marriage Countess Douglas, Countess Avondale. She the daughter of John Holland 2nd Duke Exeter and Anne Stafford Duchess Exeter. He the son of James "Gross" Douglas 7th Earl Douglas 1st Earl Avondale and Beatrix Sinclair Countess Douglas and Avondale. She a great x 2 granddaughter of King Edward III of England.

After 1464 [his father] James "Gross" Douglas 7th Earl Douglas 1st Earl Avondale and [his mother] Beatrix Sinclair Countess Douglas and Avondale were married. She by marriage Countess Douglas, Countess Avondale. The difference in their ages was 27 years. She the daughter of Henry Sinclair 2nd Earl Orkney and Egidia "Fair Maid of Nithsdale" Douglas Countess Orkney. He the son of Archibald "Grim" Douglas 3rd Earl Douglas and Joanna Strathearn Countess Douglas. They were great uncle and niece.

On 20 Feb 1473 [his step-son] Ralph Neville 3rd Earl of Westmoreland (age 17) and Isabel Booth (age 16) were married. She by marriage Baroness Neville Raby. He the son of John Neville 1st Baron Neville of Raby and Anne Holland Countess Douglas and Avondale. He a great x 3 grandson of King Edward III of England.