Katherine Daughter of Henry III
Princess Katherine, daughter of King Henry III and his queen Eleanor of Provence, is buried in Westminster Abbey. She was born at Westminster Palace on 25th November 1253 and died at Windsor Castle on 3rd May 1257. Her parents were grief stricken at her death and erected a tomb for her in the Abbey with two images in gilt bronze and silver (one was probably of St Catherine) and a silver plated wooden effigy. The location of this could have been the old Lady Chapel of 1220 (taken down when Henry VII built his chapel on the site).
For many years it was supposed that the Purbeck marble tomb now in the south ambulatory, between the chapels of St Edmund and St Benedict, was hers. This was originally free standing and has remains of the original Cosmati (mosaic) work decoration on the tomb slab but no inscription. This tomb was at one time in St Edward the Confessor's chapel but was displaced when Henry V's chantry was erected there. (It is now thought to be a tomb for two young children of Edward I, John and Henry).
"Tombs of royal babies in Westminster Abbey" by Joan Tanner, Journal of the British Archaeological Association vol.XVI, 1953
"The Cosmatesque mosaics of Westminster Abbey, vol. 2 The Royal Tombs" by Warwick Rodwell and David Neal, 2019