Little Jack Horner sat in a corner
Eating his Christmas pie.
He stuck in his thumb and pulled out a plum
And said, "What a good boy am I!"

According to legend - and the Hornor family genealogy research - Jack Horner was, in fact, Thomas Horner, a steward to the last Abbot of Glastonbury.    During the Dissolution (when King Henry VIII confiscated all monasteries), the Abbot is said to have sent some pies prepared by the monastery's renowned cook as a gift to the King. 

But these were no ordinary pies, and Thomas, who was to deliver them, was a curious young man and wondered why the pies had been baked in such secrecy and ... why pies for a King? 

Since Jack knew that travelers often hid valuables in curious places, he decided to investigate the pies.  He poked in his finger -or thumb- and found parchment documents conveying twelve manors to the King. 

A plum, indeed!  It seems the Abbot was hoping to bribe the King into sparing Glastonbury monastery.

Jack extracted one (or more, depending on who's telling the story) of the deeds and after the Dissolution, claimed ownership to the Manor of Mells in Somerset.  

A Thomas Horner did own the Manor of Mells.  His heirs owned it, in fact, until 1975, but they insist the story is untrue and that they acquired (or built) the Manor legitimately.   However, generations of Horners and Hornors, firmly believe in the story of the "enterprising" young man. 

As for the name discrepancy:  Jack   vs. Thomas,  it was common in the 15th and 16th century for any young man to be called "Jack."    And even now, anyone with the last name of Horner or Hornor, is likely to answer if you call them Jack!