How little Jack Horner became a big owner?

  According to legend, the original Horner was steward to Richard Whiting, the last of the abbots of Glastonbury. In the 1530's, the time of the Dissolution of the Monasteries, it is said that the abbot, hoping to placate Henry VIII, sent His Majesty an enormous Christmas pie containing the deeds of 12 manors. The task of carrying the pie to London was entrusted to Horner, who managed to open the pie and extract the deeds of the Manor of Mells in Somerset—presumably the "plum" mentioned in this rhyme:

Little Jack Horner sat in a corner

Eating a Christmas pie;

He put in his thumb,

And pulled out a plum,

And said "What a good boy am I"

  Certainly, one Thomas Horner did assume ownership of Mells, but both his descendants and the present owner of the house, the Earl of Oxford and Asquith, claim that the rhyme is a slander. Horner, they say, bought the manor from the King; his name wasTom and not Jack; and there is evidence that the rhyme existed before the Tudors.