

A daughter of John Segrave was likely the 1st wife of Sir William de Ferrers, 1st Baron Ferrers of Groby, but Ellen de Menteith was his widow. It is disputed which wife was mother of his children.
William Ferrers, 1st Baron Ferrers of Groby (31 January 1272 – 20 Mar 1325) was an English peer who lived under two kings, Edward I and Edward II. His baronial caput was Groby in Leicestershire.
https://en.wikipedia.org/wiki/William_Ferrers,_1st_Baron_Ferrers_of...
He was born in 1272 at Yoxall in Staffordshire, the son and heir of William de Ferrers (1240-1287),[2] of Groby in Leicestershire (a significant figure in the Second Barons' War between King Henry III and Simon de Montfort, Earl of Leicester), the younger son of William de Ferrers, 5th Earl of Derby, by his second wife Margaret de Quincy, daughter and heiress of Roger de Quincy, 2nd Earl of Winchester (c.1195-1264).[3] His mother was Anne Durward, a daughter of Alan Durward and Margery of Scotland.
William Ferrers married to Ellen de Menteith, daughter of Alexander, Earl of Menteith. They had five children, his heir, Henry, four younger sons, and a daughter.
For evidence that Sir William de Ferrers' wife was a Segrave, see Legge, Anglo-Norman Letters & Petitions (Anglo-Norman Text Soc. 3) (1941): 78–79, for a letter dated 1399/1406 from Thomas la Warre, 5th Lord Warre, to Thomas Arundel, Archbishop of Canterbury, which mentions his “cousin” [mon tesentierment amé cousin], Henry le Despenser, Bishop of Norwich. Bishop Despenser and Lord la Warre were kin by way of their common descent from the Segrave family.
http://archiver.rootsweb.ancestry.com/th/read/GEN-MEDIEVAL/2008-12/...
For evidence that the (main) wife of William de Ferrer was not a Segrave, but was Ellen de Menteith, see J. Ravilious, The Earls of Menteith: Murdoch, Earl of Menteith and the Ferrers family of Groby, The Scottish Genealogist (March 2013), Vol. LX, No. 1, pp. 12-25 PDF
“That William de Ferrers may have married a Segrave lady as his first wife seems quite likely, but the Baddesley Clinton windows should not be taken as proof of this alliance, let alone evidence that this individual was the mother of one or more of William de Ferrers children.”
J. Ravilious
https://www-personal.umich.edu/~bobwolfe/gen/mn/m26042x26043.htm
Richardson states, [2]
William de Ferrars, Knt., of Groby, Leicestershire, Stebbing, Woodham Ferrers, and Fairstead, Essex, and Newbottle and Farndon, Northamptonshire, etc. also lord of Leuchars (in Scotland), son and heir by his father's 1st marriage, born at Yoxall, Staffordshire 30 Jan. 1271/2. He married Ellen de Segrave, daugher of John de Segrave, Knt., 2nd Lord Segrave, by Christine, daughter of Hugh de Plescy, Knt., of Hooknorton and Kidlington, Oxfordshire. They had three sons, Henry [2nd Lord Ferrers of Groby], Thomas, Knt., and Ralph, Knt., and one daughter, Anne. He was summoned to perform military service in Gascony in 1294. In 1295 he was beyond seas with the Duke of Brabant. He fought at the Battle of Falkirk 22 July 1298, and was present at the Siege of Caerlaverock Castle in 1300. He was summon3d to Parliament from 29 Dec. 1299 to 24 Sept. 1324, by writs directed Willelmo de Ferariis or Willelmo de Ferrariis, whereby he is held to have become Lord Ferrers. He joined in the Baron's Letter to the Pope, 12 Feb. 1300/1, as Willilmus de Ferrariis dominus de Groby. In 1301 the Keeper of Galloway was ordered to restore to him his lands in that district, which the king, when last in those parts, had caused to be taken into his hand. He was summoned to attend the Coronation of King Edware II in 1308. His wife, Ellen, was living 9 Feb 1316/17. On 14 Feb. 1321/1. He was ordered to accompany the king against the contrariants. Sir William de Rerrers, 1st Lord Ferrers of Groby, died 29 March 1324/5.
Palmer states, [3]
William de Ferrers, summoned to parliament as baron of Groby from Jan. 26th, 1297, to Feb. 20th, 1325, when he d[ied]. He m[arried]. Elizabeth, dau[ghter]. of John lord Segrave. His son, Henry de Ferrers, [was] 3rd baron of Groby
1st Baron de Ferrers, William was an important commander in Edward I's wars in Scotland, and his arms are entered on the Falkirk Roll of 1298. He fought in Flanders in 1295 and helped mount the Siege of Carlaverock in 1300. He saw further service in Scotland in 1303, 1306, 1308 and 1311. He was summoned to many councils (parliaments) for diplomatic negotiations and ceremonial duties such as Edward II's coronation, and performed other such duties that the Barony was duly created for him.
Both [his mother] [Disproved] and daughter were married into the le Despenser family whose relationship with the Crown was so intimate.
de Ferrers, William, Lord Ferrers of Groby
Born: 30 JAN 1271, Yoxall, Staffordshire
Baptized: Yoxall, Staffordshire
Acceded: 1299 Died: 20 MAR 1324 Notes: Father: de Ferrers, William, Sir, b. 1240 Mother: Despenser, Anne le Married to de Segrave, Ellen
1272 |
January 30, 1272
|
Yoxall, Staffordshire, England
|
|
1294 |
1294
|
Groby, Leicestershire, England
|
|
1299 |
1299
|
Groby, Leicestershire, England
|
|
1315 |
April 20, 1315
|
Groby, Leicestershire, England (United Kingdom)
|
|
1317 |
1317
|
Groby, Leichestershire, ENG
|
|
1325 |
March 20, 1325
Age 53
|
Groby, Leicestershire, England
|
|
1933 |
February 25, 1933
Age 53
|
||
February 25, 1933
Age 53
|