He [Baldwin de Reviers] married, in 1257 Margaret (niece of the said Pierre and first cousin of the Queen), daughter of COUNT Thomas DE SAVOIE, sometime (1237-44) COUNT OF FLANDERS AND HAINAULT jure uxoris, by his 2nd wife, Beatrice, sister of POPE INNOCENT IV, and daughter of TEDISIO DI1 FlESCO. He died s.p.s., in France, in 1262, before 13 September, aged 26,and was buried in Breamore Priory, Hants. His widow was granted the manors of Newenham, Sawbridgeworth, and Lambeth, 4. October 1262, to hold till her dower was assigned, i.e., till 18 October following. She married, in 1269, as 2nd wife, Sir Robert AGUILLON, of Watton, Herts, Perching, Sussex, &c., who died 15 February 1285/6. She was granted the manor of Watton, 21 Feb. 1285/6, to hold till her dower was assigned, i.e., till 4 April following. She died shortly before 14 May 1292. [Complete Peerage IV:319-22, (transcribed by Dave Utzinger)]
Sources
Spouse 1: Complete Peerage of England Scotland Ireland Great Britain and the United Kingdom - G. E. Cokayne - Gloucestershire: Sutton Publishing Ltd., 2000 - [- Researched by Samuel Taylor Geer] - Book - p. IV:319-22