Who was the mother of his children?  Was she Joan de Cherleton (1st wife) or Elizabeth (2nd wife)?

Elizabeth's will explicitly refers to her sons William and Walter, but it was common usage at that time to do this for step sons.

On the other hand, we have this exchange on the medieval newsgroup:

From: royalancestry@msn.com (Douglas Richardson)
Newsgroups: soc.genealogy.medieval
Subject: Re: Joan de Cherleton, Wife of John de Beauchamp
Date: 4 Apr 2003 18:30:45 -0800

Dear Chris ~

Thank you for posting the transcript of the Beauchamp fine.  As I've
indicated in earlier posts, it appears that Joan de Cherleton was the
mother of John de Beauchamp's children, rather than his second wife,
Elizabeth, as commonly thought to be the case.  Joan's grandson,
Richard de Beauchamp, Bishop of Salisbury, was repeatedly called
kinsman by King Edward IV of England.  I show their kinship to be as
follows:


                   Roger de Mortimer, 1st Earl of March
                   =Joan de Joinville
                             /
        /-----------------------------------------
       /                                        /
Edmund de Mortimer, Knt.               Maud de Mortimer
=Elizabeth de Badlesmere        John de Cherleton, 2nd Lord Cherleton
       /                                        /
Roger de Mortimer, Earl of March       Joan de Cherleton
= Philippe de Montagu                  =John de Beauchamp, Knt.
       /                                        /
Edmund de Mortimer, Earl of March      Walter de Beauchamp, Knt.
=Philippe of Clarence                  =Elizabeth de la Roche  
       /                                        /
Roger de Mortimer, Earl of March   Richard Beauchamp,Bp. of Salisbury
=Eleanor Holand
      /
Anne Mortimer
=Richard of York, Earl of Cambridge
      /
Richard Plantagenet, Duke of York
=Cecily Neville
      /
Edward IV, King of England

Best always, Douglas Richardson, Salt Lake City, Utah

E-mail: royalancestry@msn.com

"Chris Phillips" <cgp@medievalgenealogy.org.uk> wrote in message news:<b6i8cc$a2i$1@newsg3.svr.pol.co.uk>;...
> Douglas Richardson wrote:
> > I believe you can find a published fine involving the above conveyance
> > in the following source:
> >
> > L. Drucker, Warwickshire Feet of Fines 3 (Dugdale Soc., vol. 18)
> > (1943), pg. 20.
>
> Thanks for pointing that out. As I was in the library yesterday I copied the
> published abstract, which runs as follows:
>
> DIVERS COUNTIES [?]25 Edward III
> 2041. Alcester. (Quinz. of Eas.) John son of Giles de Beauchamp
> and Joan, daughter of John de Cherleton the younger, pl. Giles
> de Beauchamp and Katherine, his wife, def. Manor of Alyncestre,
> with appurts., co Warw. 2 messuages, 175 acres of land, 4 acres
> of pasture, 23 acres of wood, 33s. 6 1/2 d. rent and rent of one
> cock and 16 hens and the fourth part of a mill in East Wycham,
> Bixle, Plumstede and Wolewych, co. Kent. Plea of covenant.
> Def. granted pl. the said manor and rendered the same to
> them in the said curt to hold to pl. and the heirs of their bodies
> of the chief lords, etc. for ever. And afterwards def. for themselves
> and heirs of Katherine granted the tenements which Simon de
> Kyngeston held for a term of seven years of the heritage of
> Katherine in the said vills the day of the making of this concord,
> with reversion to def. should remain to pl. and their heirs to
> hold etc. In default of pl.'s issue to remain wholly to
> John's right heirs. Warranty by def. and heirs of Katherine.
> Cons., 200 marks of silver. (Case 287. File 44. 454.)
> Warw. Kent.
>
> The year isn't stated explicitly, but it comes immediately after the
> Warwickshire Feet of Fines for 25 Edward III, so I guess that's the year,
> which would date it to the end of April or the beginning of May 1351.
>
> Chris Phillips