John Clifford was still under age at the time, and was not able to prove his age in order to obtain livery of his lands until 16 June 1456. He entered into his inheritance less than a month later, and was appointed a Justice of the peace in Westmorland.
John Clifford was too young to legally own his land at the time, so he couldn't get ownership until June 16, 1456. He then took possession of his inheritance shortly after that date and was appointed as a Justice of the peace in Westmorland.