sentences:  However he had little financial benefit from his inheritance as a result of the very large jointure which had been awarded to Elizabeth Segrave's mother, Margaret, Duchess of Norfolk, who lived until 1399.In 1368 he also succeeded to the barony of Mowbray when his father was slain by the Turks near Constantinople while en route to the Holy Land.In April 1372, custody of both John and his brother Thomas was granted to Blanche Wake, a sister of their grandmother, Joan of Lancaster.