The text below is from: http://familyarchive.lefora.com/2009/09/22/guillory-origins/
“The Guillory Surname is Latin in origin and is a derivative of "William" or in French "Guillaume."
There is mention of Guillory being an old Latin name located in Drome, Rhone-Alps, and the Languedoc Regions of France.
The name has been spelled in a variety of spellings: Guillory, Guillery, Guillori, Guillauri, Guillari, Guillore, etc.
The earliest mention of a "Guillory" that I have found so far, is Louis Guillori in 1466, a Judge Prevost, in LaRochelle, France.
In 1512, Holy Roman Empire, Etienne Guillery was a printer of books. (a rare document was auctioned at Christie's in London) and there is a woodcutting of an early game piece that Etienne printed.
There was a Guillery highwayman who is said to haunt the place where he died.
In 1608 there was a Phillippe Guillery, a former high official of the King's Guard who was executed by Henri IV, King of France. The usual method was to take the condemned to the church and hang or execute them in the doorway. Crowds came to see it done. Guess where he was executed? LaRochelle, at Saint Sauveur.
In 1612, there was a Jacques Guillery who was a printer in France.”