Complex sentence: On 14 September 1444 he was created Duke of Buckingham, making him one of the greatest landowners in England; in 1447 he was granted precedence over all English dukes not of royal blood.
Split into simpler sentences: On 14 September 1444, he was created Duke of Buckingham, making him one of the greatest landowners in England. In 1447, he was granted precedence over all English dukes not of royal blood.