William was closely associated with King Edward III from the early years of Edward's reign until his (William's) death. In 1330 he helped the king seize and arrest Roger Mortimer, Earl of March, who up till then had been de facto in control of government.
In the 1330s he fought in Scotland, and in 1336 was one of those commissioned to negotiate a truce between England and Scotland.
On 16 March 1336/7 he was given the title of Earl of Northampton. He was granted annuities from customs revenues to supplement revenue from estates, in order to ensure his income was sufficient to maintain the status of an earl. In 1338 he became Constable of England for life.
He was involved in talks with the French in 1337, and subsequently with potential allies for war against France. He took part in fighting in the early part of the Hundred Years' War, taking a leading part in the English naval victory at Sluys in 1340 and campaigns in France that followed. In 1340 he was briefly held in Flanders as hostage for Edward III's debts, but managed to flee from Ghent to England with the king.
In 1341, when there were difficulties between Edward III and Archbishop John Stratford, who had been King Edward's Chancellor, he represented the king in discussions with the Archbishop and was one of the lords who heard charges against him.
In the 1340s he took part in fighting in Brittany, Scotland and France, including the Battle of Crécy in 1346 and the Siege of Calais.
He was made a Knight of the Garter in 1349, when a vacancy arose.
In 1351 he was appointed Warden of the Scottish Marches and Admiral of the North.
In 1359/60 he was back fighting in France, and he was a witness to the Treaty of Brétigny on 8 May 1360.
Death and burial
William died on 16 September 1360, a date proven by an Inquisition Post Mortem. He was buried at Walden Abbey, Essex.
The Inquisition of William de Bohun Earl of Northampton took place in October 1360 through to January 1360/1361. He was seised of lands in Kent, Surrey, Nottinghamshire, Berkshire, Oxfordshire, Essex, Suffolk, Rutland, Lincoln, Buckinghamshire and Shropshire. There was some variation regarding the date of his death, one of those dates being 16 Sep 1360. His heir was his son Humphrey de Bohun of age variously given as 18 to 20.
The 1846 revised edition of Monasticon Anglicanum, in its pages on the Abbey of Llanthony, incorrectly gives William's death date as 1450.
On 13 August 2014 Season 5 Episode 4 of the US version of the TV programme Who Do You Think You Are? discussed the descent of the actress Valerie Bertinelli from William de Bohun.
Richardson, Douglas. Royal Ancestry: A Study in Colonial and Medieval Families, 5 vols, ed. Kimball G. Everingham. Salt Lake City: the author, 2013. See also WikiTree's source page for Royal Ancestry. Additional Royal Ancestry citations (originally from Lewis):
Vol. I, pp 424-5
Vol. IV, pp 172 and 188
Richardson, Douglas. Magna Carta Ancestry: A Study in Colonial and Medieval Families, 4 vols, ed. Kimball G. Everingham. 2nd edition. Salt Lake City: the author, 2011. See also WikiTree's source page for Magna Carta Ancestry.
Cokayne, G E. Complete Peerage, revised and enlarged, Vol. IX, St Catherine Press 1936, pp. 664-667: BOHUN VI
Oxford Dictionary of National Biography: Bohun, William de, first earl of Northampton (published 2004, revised online 2008, available online via some libraries)
Dugdale, William, Monasticon Anglicanum, new and enlarged edition, Vol. VI, pub. James Bohn 1846
I deleted "(bur.) Walden Abbey, Essex, England" from the death location field. It is where he was buried, but I couldn't find confirmation that he died in Essex (or even in England, although it may be inferred that he had returned by the statement "In 1357-9, he was abroad in Gascony." [Richardson's Magna Carta Ancestry, I:244 BOHUN 6], his profile says he was fighting in France 1359-60 and "was a witness to the Treaty of Brétigny on 8 May 1360").
Over several edits I have eliminated large chunks of information about descendants which belongs to their profiles and was already in them; and replaced a bio text that was entirely copied-and-pasted from two websites (for one of them, which is partially inaccurate and entirely unsourced, with no attribution) with a sourced factual bio. I may make further minor changes, but the main work I intended is now done.
Further to the comment I have just added, a lot of this profile as it currently stands is about his descendants, and is covered in their profiles. And it looks as if there is a large amount of copying and pasting from elsewhere. So I think it may be more than "a little" work that I will need to do.
De Bohun-273 and Bohun-35 appear to represent the same person because: Major difference in birth dates, but obviously intended to be the same person, based on relationships and title. Bohun is the preferred LNAB based on European Aristocrats project naming standards.