Question: Who is the paternal grandfather of Eleanor De Bohun?

Knowledge 1: Eleanor de Bohun
Lady Eleanor de Bohun (– 3 October 1399) was the elder daughter and co-heiress with her sister, Mary de Bohun, of their father Humphrey de Bohun, 7th Earl of Hereford (1341–1373).Her mother was Lady Joan Fitzalan, daughter of Richard FitzAlan, 10th Earl of Arundel and his second wife Eleanor of Lancaster. [SEP] Knowledge 2: Humphrey de Bohun, 7th Earl of Hereford
Humphrey de Bohun, 7th Earl of Hereford, 6th Earl of Essex,2nd Earl of Northampton, KG (25 March 1341 – 16 January 1373) was the son of William de Bohun, 1st Earl of Northampton and Elizabeth de Badlesmere, and grandson of Humphrey de Bohun, 4th Earl of Hereford by Elizabeth of Rhuddlan, daughter of King Edward I.He became heir to the Earldom of Hereford after the death of his childless uncle Humphrey de Bohun, 6th Earl of Hereford.Following King PeterI's visit to England, Humphrey participated in the sack of Alexandria in 1365.His wife and the mother of his daughters was Joan Fitzalan, daughter of Richard Fitzalan, 10th Earl of Arundel and Eleanor of Lancaster, whom he married after 9 September 1359.On his death, his great estates were divided between his two surviving daughters:
Knowledge 1: Eleanor de Bohun
Lady Eleanor de Bohun (– 3 October 1399) was the elder daughter and co-heiress with her sister, Mary de Bohun, of their father Humphrey de Bohun, 7th Earl of Hereford (1341–1373).Her mother was Lady Joan Fitzalan, daughter of Richard FitzAlan, 10th Earl of Arundel and his second wife Eleanor of Lancaster. [SEP] Knowledge 2: Humphrey de Bohun, 2nd Earl of Hereford
Humphrey( IV) de Bohun( 1204 – 24 September 1275) was 2nd Earl of Hereford and 1st Earl of Essex, as well as Constable of England.He was the son of Henry de Bohun, 1st Earl of Hereford, and Maud FitzGeoffrey.
Knowledge 1: Henry de Bohun
Sir Henry de Bohun( died 23 June 1314) was an English knight, the grandson of Humphrey de Bohun, 2nd Earl of Hereford.He was killed on the first day of the Battle of Bannockburn by Robert the Bruce.Riding in the vanguard of heavy cavalry, de Bohun caught sight of the Scottish king who was mounted on a small palfrey"( ane gay palfray Li till and joly)" armed only with a battle- axe.De Bohun lowered his lance and charged, but Bruce stood his ground.At the last moment Bruce manoeuvred his mount nimbly to one side, stood up in his stirrups and hit de Bohun so hard with his axe that he split his helmet and head in two.Despite the great risk the King had taken, he merely expressed regret that he had broken the shaft of his favourite axe.An iconic description and picture of the death of Henry de Bohun is contained in" Scotland's Story" by H. E. Marshall. [SEP] Knowledge 2: Eleanor de Braose
Eleanor de Braose( c. 1228–1251) was a Cambro- Norman noblewoman in Great Britain, and a wealthy co-heiress of her father, who was the powerful Marcher lord William de Braose, and of her mother, Eva Marshal, a co-heiress of the Earls of Pembroke.Her husband was Humphrey de Bohun, heir of the 2nd Earl of Hereford, by whom she had children, including Humphrey de Bohun, 3rd Earl of Hereford.

Answer: William de Bohun, 1st Earl of Northampton