Constance was Alan's first wife (Williamson, David. Debrett's kings and queens of Britain. Topsfield, Mass. : Salem House Publishers, 1986, pg. 43).
It was said she was the most highly gifted of all of the Conqueror's daughters. As she was the favourite of her mother, she was offered later in marriage, in 1086, to Alan IV of Brittany, and the two were married at Caen, Normandy.[1] Constance died childless, perhaps poisoned, on 13 August 1090, and was buried in the Church of St. Melaine, in St Melans, Redon.
In 1672, her tomb was discovered and opened. Inside were some fragments of a woollen material which at the time the body had been wrapped in and a leaden cross with her epitaph engraved with the name of her father, husband, and date of death (wikipedia)