http://fmg.ac/Projects/MedLands/ENGLISHNOBILITYMEDIEVAL3T-Z.htm#dau...

Cawley (see above) *is* capable of making mistakes, and in this case I don't think he thought things through, or else relied too heavily on "traditional" secondary sources. It simply is not possible that Matilda was a Clare AND sister to a Treasurer of York - she most certainly was not and could not have been sister to Bevis/Bogo de Clare, the late 13th century benefice-hog. who would have been her great-grandson. Bogo de Clare, Clerk

There are no other recorded Clare treasurers of York in this time period.

(There are no recorded Clere treasurers either, but there was a William no-last-name who was treasurer from 1118-1122.) William, treasurer of York Minster - presumptively her brother. He is mentioned, with no family name, in charters and accounts 1218-1222. Succeeded as treasurer by 19 June 1222, by one William de Rotherfield. (There were three Williams active in the York ecclesiastical hierarchy circa 1220, per a charter of Archbishop Gray dated 3 Sep. 1220, witnessed by William 'the treasurer,' William 'Archdeacon of the East Riding,' and William 'Archdeacon of Richmond' - that last apparently being de Rotherfield and the other two being of unknown families.)

Extensive and inconclusive discussion here: www.findagrave.com

Maude De Clare De Lacy
BIRTH 1180
South Yorkshire, England
DEATH unknown
BURIAL
Burial Details Unknown
MEMORIAL ID 111113537

Maude (de Clare/De Clere) was the sister of the Treasurer of York Cathedral. She married in Lincolnshire to Roger FitzRichard who had adopted the surname de Lacy. Roger's father Sir John FitzRichard was founder of Stanlaw Abbey. His son and grandson and their families were all interred at the Cistercian Abbey of Stanlaw. Records of de Clare family indicate Maude, wife of Roger, was interred with her husband at Stanlaw. The Abbey records do not indicate her burial there, so we are noting the place of burial at this time as "unknown."
Family Members
Parents

Richard de Clare
1153–1217
Amice FitzWilliam Clare
1160–1225

Spouses
William de Braose
1175–1210
Sir Roger de Lacy
1172–1212

Siblings
Sir Gilbert de Clare
1180–1230

Children
Walter De Braose
1206–1234https://groups.google.com/g/soc.genealogy.medieval/c/EDthyh06leQ