Biography of William Sinclair 3rd Earl Orkney 1st Earl Caithness 1410-1484
Paternal Family Tree: Sinclair
Maternal Family Tree: Margaret Graham Countess Ross
William Sinclair 3rd Earl Orkney 1st Earl Caithness and Elizabeth Douglas Countess Buchan and Orkney and Caithness were married. She by marriage Countess Orkney. She the daughter of Archibald Douglas 1st Duke Touraine and Margaret Stewart Duchess Touraine. He the son of Henry Sinclair 2nd Earl Orkney and Egidia "Fair Maid of Nithsdale" Douglas Countess Orkney. They were half first cousin once removed.
William Sinclair 3rd Earl Orkney 1st Earl Caithness and Janet Yeman Countess Orkney and Caithness were married. She by marriage Countess Orkney, Countess Caithness. He the son of Henry Sinclair 2nd Earl Orkney and Egidia "Fair Maid of Nithsdale" Douglas Countess Orkney.
In 1407 [his father] Henry Sinclair 2nd Earl Orkney (age 32) and [his mother] Egidia "Fair Maid of Nithsdale" Douglas Countess Orkney (age 27) were married. She by marriage Countess Orkney. She a great x 5 granddaughter of King John "Lackland" of England.
In 1410 William Sinclair 3rd Earl Orkney 1st Earl Caithness was born to Henry Sinclair 2nd Earl Orkney (age 35) and Egidia "Fair Maid of Nithsdale" Douglas Countess Orkney (age 30).
Around 1420 [his father] Henry Sinclair 2nd Earl Orkney (age 45) died. His son William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 10) succeeded 3rd Earl Orkney.
In 1436 [his son] William Sinclair 2nd Lord Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 26) and Elizabeth Douglas Countess Buchan and Orkney and Caithness. Coefficient of inbreeding 2.40%.
Around 1438 [his mother] Egidia "Fair Maid of Nithsdale" Douglas Countess Orkney (age 58) died.
In 1440 [his daughter] Catherine Sinclair Duchess Albany was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 30) and Elizabeth Douglas Countess Buchan and Orkney and Caithness. Coefficient of inbreeding 2.40%.
Around 1440 [his daughter] Katherine Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 30) and [his future wife] Marjory Sutherland Countess Orkney and Caithness.
Before 1448 William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 38) and Marjory Sutherland Countess Orkney and Caithness were married. She by marriage Countess Orkney, Countess Caithness. He the son of Henry Sinclair 2nd Earl Orkney and Egidia "Fair Maid of Nithsdale" Douglas Countess Orkney.
In 1448 [his son] Robert Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 38) and [his wife] Marjory Sutherland Countess Orkney and Caithness.
Around 1450 [his daughter] Margaret Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 40) and [his wife] Marjory Sutherland Countess Orkney and Caithness.
Around 1451 [his daughter] Susan Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 41) and [his wife] Marjory Sutherland Countess Orkney and Caithness.
Around 1452 [his son] Arthur Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 42) and [his wife] Marjory Sutherland Countess Orkney and Caithness.
In 1452 [his son] Oliver Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 42) and [his wife] Marjory Sutherland Countess Orkney and Caithness.
Around 1453 [his son] George Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 43) and [his wife] Marjory Sutherland Countess Orkney and Caithness.
Around 1454 [his son] Alexander Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 44) and [his wife] Marjory Sutherland Countess Orkney and Caithness.
Around 1455 [his daughter] Elizabeth Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 45) and [his wife] Marjory Sutherland Countess Orkney and Caithness.
In 1455 William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 45) was created 1st Earl Caithness. Elizabeth Douglas Countess Buchan and Orkney and Caithness by marriage Countess Caithness.
Around 1455 [his daughter] Marjory Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 45) and [his wife] Marjory Sutherland Countess Orkney and Caithness.
Around 1455 [his daughter] Mariota Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 45) and [his wife] Marjory Sutherland Countess Orkney and Caithness.
In 1457 [his daughter] Eleanor Sinclair Countess Atholl was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 47) and [his wife] Marjory Sutherland Countess Orkney and Caithness.
After 29 Apr 1458 [his son] William Sinclair 2nd Lord Sinclair (age 22) and [his daughter-in-law] Christian Leslie Lady Sinclair were married. He the son of William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 48) and Elizabeth Douglas Countess Buchan and Orkney and Caithness.
In 1459 [his son] William Sinclair 2nd Earl Caithness was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 49) and [his wife] Marjory Sutherland Countess Orkney and Caithness at Ravenscraig Castle.
Around 1470 [his daughter] Euphemia Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 60) and [his wife] Marjory Sutherland Countess Orkney and Caithness.
Before Apr 1475 [his son-in-law] John Stewart 1st Earl Atholl (age 35) and [his daughter] Eleanor Sinclair Countess Atholl (age 18) were married. She by marriage Countess Atholl. She the daughter of William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 65) and Marjory Sutherland Countess Orkney and Caithness. 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. 
Before 1477 [his son-in-law] Alexander Stewart 1st Duke Albany (age 23) and [his daughter] Catherine Sinclair Duchess Albany (age 36) were married. She by marriage Duchess Albany. The marriage was subsequently regarded as illegitimate. She the daughter of William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 66) and Elizabeth Douglas Countess Buchan and Orkney and Caithness. He the son of King James II of Scotland and Mary of Guelders Queen Consort Scotland. They were second cousins. He a great x 3 grandson of King Edward III of England.
In 1479 [his daughter] Katherine Sinclair (age 39) died.
Around 1480 [his daughter] Marjory Sinclair (age 25) died.
In 1484 William Sinclair 3rd Earl Orkney 1st Earl Caithness (age 74) died. His son [his son] William Sinclair 2nd Earl Caithness (age 25) succeeded 2nd Earl Caithness. [his son] William Sinclair 2nd Lord Sinclair (age 48) was appointed 2nd Lord Sinclair.
[his son] David Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness.
[his daughter] Unamed Sinclair was born to William Sinclair 3rd Earl Orkney 1st Earl Caithness and Elizabeth Douglas Countess Buchan and Orkney and Caithness. Coefficient of inbreeding 2.40%.
[his father] Henry Sinclair 2nd Earl Orkney succeeded 2nd Earl Orkney.
Alexander Stewart and [his mother] Egidia "Fair Maid of Nithsdale" Douglas Countess Orkney were married. He the son of Murdoch Stewart 2nd Duke Albany and Isabel Countess Lennox Duchess Albany. They were half first cousin once removed. She a great x 5 granddaughter of King John "Lackland" of England. 
Kings Wessex: Great x 11 Grand Son of King Edmund "Ironside" I of England
Kings Gwynedd: Great x 7 Grand Son of Owain "Great" King Gwynedd
Kings Seisyllwg: Great x 13 Grand Son of Hywel "Dda aka Good" King Seisyllwg King Deheubarth
Kings Powys: Great x 8 Grand Son of Maredudd ap Bleddyn King Powys
Kings England: Great x 6 Grand Son of King John "Lackland" of England
Kings Scotland: Great x 3 Grand Son of Robert "The Bruce" I King Scotland
Kings Franks: Great x 18 Grand Son of Louis "Pious" King Aquitaine I King Franks
Kings France: Great x 11 Grand Son of Robert "Pious" II King France
Father: Henry Sinclair 2nd Earl Orkney
William Sinclair 3rd Earl Orkney 1st Earl Caithness 6 x Great Grand Son of King John "Lackland" of England
Great x 4 Grandfather: William "Longleg" Douglas
Great x 3 Grandfather: William "Hardy" Douglas 2nd Lord Douglas
Great x 4 Grandmother: Constance Battail Battail
Great x 2 Grandfather: James "Black" Douglas
Great x 4 Grandfather: Alexander Stewart 4th High Steward
Great x 3 Grandmother: Elizabeth Stewart Baroness Douglas
Great x 1 Grandfather: Archibald "Grim" Douglas 3rd Earl Douglas
GrandFather: William "Nithsdale" Douglas
Mother: Egidia "Fair Maid of Nithsdale" Douglas Countess Orkney 5 x Great Grand Daughter of King John "Lackland" of England
Great x 4 Grandfather: Alexander Stewart 4th High Steward
Great x 3 Grandfather: James Stewart 5th High Steward
Great x 2 Grandfather: Walter Stewart 6th High Steward
Great x 1 Grandfather: King Robert II of Scotland 3 x Great Grand Son of King John "Lackland" of England
Great x 4 Grandfather: Robert Bruce Earl Carrick 4 x Great Grand Son of King Henry I "Beauclerc" England
Great x 3 Grandfather: Robert "The Bruce" I King Scotland 5 x Great Grand Son of King Henry I "Beauclerc" England
Great x 4 Grandmother: Marjorie Carrick 3rd Countess Carrick
Great x 2 Grandmother: Marjory Bruce 2 x Great Grand Daughter of King John "Lackland" of England
Great x 4 Grandfather: Donald Mar 7th Earl Mar
Great x 3 Grandmother: Isabella Mar Great Grand Daughter of King John "Lackland" of England
Great x 4 Grandmother: Elen ferch Llewellyn Aberffraw Countess Huntingdon and Mar Grand Daughter of King John "Lackland" of England
GrandMother: Princess Egidia Stewart 4 x Great Grand Daughter of King John "Lackland" of England
Great x 2 Grandfather: Hugh 4th Earl Ross
Great x 1 Grandmother: Euphemia Ross Queen Consort Scotland
Great x 3 Grandfather: John Graham of Abercorn
Great x 2 Grandmother: Margaret Graham Countess Ross