'Robert Grosvenor of Holme son and heir, was under age 21 Edw. I. in which year the abbot defended his right to the wardship of the said Robert, against Richard de Lostock, ...'
↑ Birth year estimated based on the fact that he was known to be a minor and a ward in 1293, and did homage in 1305 (presumably indicating that he had just reached his majority).