Thomas was the youngest surviving legitimate son of Edward III and Philippa of Hainhault. He was born in 1355.
He married the co-heiress Eleanor de Bohun and moved into Pleshey Castle. Once ensconced he tried to persuade his young sister-in-law Mary de Bohun that what she really wanted to be was an impoverished nun leaving him to inherit everything by right of his wife. His mother-in-law and her sister had other ideas, conferred with Thomas’s older brother John of Gaunt and the next thing that Thomas knew was that his nephew Henry of Bolingbroke had married Mary.
Richard II created him Earl of Essex by right of his wife who was the elder of the two sisters and in 1385 he was made Earl of Aumale and Duke of Gloucester. Rather ungratefully in light of the titles Thomas was one of the Lords Appellant which not only put him at odds with his nephew Richard II but also with the family of his brother Edmund of Langley who were part of the Counter-Appellant faction. Ultimately Richard was revenged upon his uncle by having him arrested, taken to Calais and murdered.
Thomas and Eleanor had five children -the eldest was a boy. Philippa died young and Isobel became a nun. After his father’s arrest Humphrey was made a ward of the Crown – he was a Plantagenet after all. Richard took him and the son of Henry of Bolingbroke to Ireland with him in 1398 but Humphrey died before he could be reunited with his mother. Isabel de Bohun died soon after her son.
Anne of Gloucester was born in 1383 and married three times- firstly to Thomas Stafford, 3rd Earl of Stafford. He died in 1392 about two years after the marriage which was not consummated. His older brother Ralf was murdered by John Holland ( Richard II’s half brother, Elizabeth of Lancaster’s husband, Henry of Bolingbroke’s brother-in-law.) Husband number two was Edmund Stafford – the 5th Earl and Thomas and Ralf’s brother (there was another brother in between who was the 4th earl.)
Anne and Thomas had children –
Humphrey Stafford became the 1st Duke of Buckingham. He married a cousin – Anne Neville, the daughter of the Earl of Westmorland and John of Gaunt’s daughter Joan Beaufort. Apparently Humphrey and Anne had somewhere in the region of twelve children but we are going to leave them alone for another day – suffice it to say there were many marriages of cousins including a couple of Margaret Beauforts covered in previous posts.
Anne Stafford married Edmund Mortimer, 5th Earl of March – another cousin, rightful king of England in the eyes of supporters of Richard II and anti-Henry factions. The pair had no children. After Edmund’s death in 1425 she married John Holland the second Duke of Exeter – another cousin. This particular Holland was the son of the murderous John Holland (the one who killed Anne’s Uncle Ralph)and Elizabeth of Lancaster.
Philippa Stafford died young.
As for Ann Stafford and John Holland’s children there were a son and a daughter. Henry Holland became the 3rd Duke of Exeter. Despite being married to Richard of York’s daughter Anne (yet another cousin) he remained a Lancastrian and the marriage was not a happy one. He spent some time in the Tower once Edward IV was on the throne but went with Edward to France in 1475. He unaccountably fell overboard and drowned on the homeward journey – no one was particularly upset and his only legitimate child pre-deceased him.
Anne Stafford’s daughter was also named Anne. She was born somewhere about 1430 and like her mother was married three times. Firstly she married John Neville (another cousin) who died. Then she married John’s uncle somewhat confusingly also called John and a nightmare to explain on the papal dispensation I should imagine. He was killed at Towton. Then Anne married James Douglas the Earl of Douglas.
And finally back to Anne Stafford who was, you may remember, married three times. Her third husband was William Bourchier, Count of Eu. There were children and the was the whole cousin intermarriage business all over again.
It would perhaps have been easier to identify the leading families who were not descended from Edward III, Edward I or Henry III! History does not happen in a vacuum. The Wars of the Roses did not spring fully formed from the void caused by Henry VI’s breakdown. It was a family squabble that escalated across the generations and it was quite clearly not a cut and dried question of which side you were on given that the key families were like a board of directors running a family firm with increasingly hostile takeover bids being actioned!
As for the probability of being descended from Edward III – follow this link for the mathematics: http://community.dur.ac.uk/a.r.millard/genealogy/EdwardIIIDescent.php
If you wish to look more closely at Edward III’s descendants then this website is a good starting point: https://www.genealogics.org/descendtext.php?personID=I00000811&tree=LEO&generations=
Weir, Alison. Britain’s Royal Families.