From BP
3:
...in the 29th Edward I was in the Scottish wars, but in the next reign joined in the great insurrection of Thomas, Earl of Lancaster and, being made prisoner with that nobleman at the battle of Boroughbridge in 1322, was hanged at York immediately afterwards.
Note that this death death of 1322 conflicts with TCP
1 who has him dead by 1294.
Another conflict lies with his spouse. Per BP
3 and BEP
2, this William married Agnes Grey, daughter of Richard, Lord Grey of Codnor. TCP is silent on his wife. But Baildon
4 says that William married Agnes Metham, daughter of Sir John Metham and was dead by 1294.
Footnotes
[1]
The Complete Peerage of England, Scotland, Ireland, Great Britain and the United Kingdom, Extant, Extinct or Dormant (2nd Edition, 1926); GE Cockayne; Volume 5, pages 518-520
[2]
A Genealogical History of the Dormant, Abeyant, Forfeited and Extinct Peerages of the British Empire (New Edition), by Sir John Bernard Burke, London, 1866. Fitzwilliam, Earl of Southampton (page 216)
[3]
Burke's Peerage, 99th Edition (1949), Fitzwilliam (pages 769-770)
[4]
Baildon and the Baildons, a History of a Yorkshire Manor and Family, by W Paley Baildon, Volume 1, page 353
