William Ros, 1st Baron Ros


William Ros or Roos, 1st Baron Ros of Helmsley, was one of the claimants of the crown of Scotland in 1292 during the reign of Edward I.

Family

William Ros was the eldest son of Robert de Ros of Helmsley, Yorkshire, and Isabel d'Aubigny, daughter and heiress of William D'Aubigny of Belvoir, Leicestershire, and granddaughter of William d'Aubigny. He had four brothers and three sisters:
On 24 December 1264, William's father, Robert de Ros, was summoned to Simon de Montfort's Parliament in London as Robert de Ros, and for some time it was considered that the barony was created by writ in that year, and that Robert de Ros was the 1st Baron Ros. According to The Complete Peerage:
In 1616, the barony of Ros was allowed precedence from this writ , a decision adopted by the Lords in 1806 ; but these writs, issued by Simon in the King's name, are no longer regarded as valid for the creation of peerages.

Accordingly, the barony is now considered to have been created when William Ros was summoned to Parliament from 6 February 1299 to 16 October 1315 by writs directed Willelmo de Ros de Hamelak.
William Ros succeeded to the family honours and estates on the death of his mother. He was an unsuccessful competitor for the crown of Scotland, founding his claim on his descent from his great grandmother, Isabel, a bastard daughter of William I of Scotland. He was buried at Kirkham Priory. He was involved in the wars of Gascony and Scotland. He discovered that Robert de Ros, Lord of Werke, intended to give up his castle to the Scots. William notified the king of this, who sent him with a thousand men to defend that place. The place was then forfeited because of the treason of Robert de Ros. William Ros then took possession of it. William was appointed warden of the west Marches of Scotland.
Through his marriage to Maud de Vaux the patronage of Penteney and Blakeney Priories in Norfolk and of Frestun in Lincolnshire came into the Ros family.

Marriage and issue

William Ros married, before 1287, Maud de Vaux, younger daughter and coheiress of John de Vaux, by whom he had four sons and four daughters.