On Saturday, 27 March 1999 at 09:00:00 UTC+1, Francisco Antonio Doria wrote:
> >01. Sir WILLIAM CHAMBERLAIN, of North Reston, Lincolnshire. Before 1274,
> >John
> >Lindsey conveyed Petsoe Manor, Buckinghamshire to him in exchange for other
> >lands. On 11 Oct 1274, as William Chamberlain, Lord of Petsoe, he
> >presented to
> >Petsoe St. James and did so again in June 1275 (Liscomb's Bucks, 4: 136)..
> >On 4
> >April 1280, William le Chaunbrelayn and Joan, his wife, acknowledge a
> >tresspass
> >(Cal. Close Rolls, 1279-88: 47). He was dead by 1284 when his widow,
> >Joan, was
> >holding Petsoe (Feudal Aids, 1: 82 wherein she is erroneously called
> >'Johannes.').
> > Married by 4 Apr 1280 to JOAN. She is called Joan Chamberlain in 1302
> >(Feudal Aids, 1: 104)
> I envy you, and wonder about the manifold ways of keeping official registers. I have no such detail neither in my Italian ancestry (see Litta's tables on the Acciaioli, or the more recent, very well documented, Raveggi et al, _Ghibellini, Guelfi e Popolo Grasso_) nor in my Portuguese lines. For the scarcity of documents on major Portuguese families, take a look at Braancam Freire's discussion of the descent from Martim Afonso Chichorro, bastard of King Afonso III, and ancestor of the Sousa do Prado family. (There was a confusion in two of the early generations of that family, only settled in this century, in the late '60s - and that without explicit documents, just with indirect references.)
> Lucky you! Best,
> Chico Doria
> PS: For more of such problems see my recent discussion on the Vasconcellos with Eduardo de Vasconcellos.
> Francisco Antonio Doria
> Prix Caumont-La Force 1995
> (Conféderation Internationale de Généalogie et d'Héraldique.)
> fad...@rio.com.br
> http://www.rio-v.com/costadoria
> Tels.: 021-547-5541/024-231-4133/021-9943-6968
> All material posted is copyrighted. Please refer to the author to quote it.

Further research has revealed the following:

See: Bland, Alfred Edward; Davies, Percival Vaughn; Dawes, Michael Charles Burdett., (1911)., Calendar of the Fine Rolls preserved in the Public Record Office. Vol.1., (pp.17, 302, 317)., London, H.M. Stationery Office. Retrieved from the Internet Archive, here: https://archive.org/details/calendaroffinero01lond/page/16/mode/2up

Sir Richard 'le Chamberlain', Kt. was born in about 1267, the son of Peter le Chaumbreleyn alias le Chaumberleng and his wife Isabel de Fayntre, third of the five daughters of Adam de Fayntre. He is the Sir Richard le Chamberlain, Kt, who married Joan de Gatesden.
See also:
Harleian Society., (1869)., The Publications of the Harleian Society. London: The Society. Retrieved from the Internet Archive, here: https://archive.org/details/publicationsofha80harluoft/page/188/mode/2up

I'm aware that this messes up the lineage at the top of the line, and am hoping for a breakthrough.

For most recent research, see:
https://www.wikitree.com/wiki/Chamberlain-1627