William's older brother, Richard (died before 1335), was still alive in 1315, as evidenced by:
1315 Court at Halifax, Monday next after Feast of St Luke the Evangelist, Tourn there the same day, the 12 jurors: William de Sothill junior, Thomas de Waddesworth, Richard son of John de Stansfeld, John Culpon, William de Rydyng, and others (Wakefield Court Rolls
The evidence given below for William, heir following his brother Richard's death, has been subdivided into confirmed, likely, possible, and questionnable - confused somewhat by his having had a son William who also appears in records during overlapping periods.Confirmed
1335 Grant by William son of John de Stansfeild' to Sir John de Eland, knight, of the reversion after the death of his brother Richard in a tenement etc. Attached is another, rough, copy of the charter (Exley, Yk).
(Notts Archives: Savile of Rufford: Deeds & Estate Papers DD/SR/28/1/19)
1335 Grant by William son of John de Stansfeld' to Sir John de Eland, knight, of the homage and service of Richard de Ekkleslay and other for tenements and lands (Southowram, Lindley and Northowram).
(Notts Archives: Savile of Rufford: Deeds & Estate Papers DD/SR/28/1/20)
3 May 1335 Grant by John de Carleton of Norton to Wm de Myrfeld of all his lands etc in Hetonclak, Scholes and Okeneschagh, with all his bondmen (nativis) there with their chattels and issue. Ledes [Leeds], Sunday, the Invention of the Cross, 29 Edward III. Witnesses Sir Simon Warde, Sir Nic. de Wortlay, Sir Chr. Maillore, knts., John de Clocher, John de Sheffeld, John de Seyvilla, Nic. de Gyselay, John de Norton, William de Nevill, Wm de Beston, Wm de Stansfeld, Hugh de Copley, Adam de Helay of Mirfeld, Ric. de Helay.
(Yorkshire Archaeological Journal volume 8 p256)
8 June 1350 Feoffment : Richard son of Richard son of Adam de Waddesworth to Henry son of William de Sothill. Property: Cremlesworth field and other lands in Wadsworth. Witnesses: Willam de Stansfeld, William his son. Thomas Culpan, Thomas de Soothil de Hill, William son of William son of William Halif, Thomas del Hyrst. Given at Heptonstall.
(West Yorkshire Archive Service: Calderdale MISC:205/6)The following records are likely, but not certain, to be this William de Stansfeld:-
6 Dec 1308 Court at Halifax. Tourn there the same day, Sourby: John de Hertlay drew blood from William de Stansfeld; 12d.
(Wakefield Court Rolls (Cambridge Edition) Volume 2)
6 Nov 1316, Court held at Halifax. William de Stansfeld received Robert de Myddelton an common ill-doer in the lord's chase at the Nativity of St John the Baptist. To be attached.
Henry de Lacey, Hugh de Copley and William de Stansfeld stole a horse worth 20s from Ellen of Langfeld. To be taken. William de Stansfeld drew blood from William son of Peter of the croft. Amerced 2s.
(Wakefield Court Rolls Volume 4 p147-148)
1 Nov 1318 at York. Pardon, with the assent of the Parliament at York, to Roger de Herdeby,
an adherent of Thomas, earl of Lancaster, the robbery of G. cardinal
priest of SS. Marcellinus and Peter, and Luke, cardinal deacon of St. Mary
in Via Lata, excepted. By K. and C........The like for the under-mentioned adherents of the earl of Lancaster, viz........a long list of names follows, including William de Stanfeld.
(Patent Rolls Edward II Vol 3 membrane 16 p233)
Note: there are 11 pages of pardons to a great number of people, often shown as lists and sometimes interspersed with detailed records of individual pardons.The following records could be this William but could also be his son William:-
12 May 1349 Tourn at Halifax, on the oath of Wiliam de Stansfeld, Hugh de Coppelay, Thomas Culpon, Richard de Waddeswrith junior, Richard del Wod, Richard de Estwod, William del Rydyng, Richard de Northland, and others
(Wakefield Court Rolls).
17 May 1350 Tourn at Halifax, by oath of William de Stansfeld, Hugh de Coplay, Richard de Waddeswrith, Thomas Culpon, William de Estwod, William son of Thomas de Heptonstall, William Tayllour and others
[Wakefield Court Rolls].
25 October 1350 Tourn at Halifax, on the oaths of Hugh de Coplay, William de Stansfeld, Thomas Culpon, William de Coplay and others
(Wakefield Court Rolls).
The following may be of relevance but must be considered questionnable:-
There are a number of entries in the Calendar of Patent Rolls
listing men appointed as Purveyors for Queen Isabella's household. A William de Stanesfeld appears on these lists numerous times between 1328 and 1345.