Does anyone know what this means?

My Paternal Grandmother used to say we were related to a signer of the Declaration of Independence through her family. That he was Governor of Massachusetts and the vice president of the United states.  Elbridge Gerry is best known for his attempted restructuring of the tax districts of Massachusetts "Gerrymandering". But according to this biography he was directly responsible for the Boston Tea Party and personally funded the purchase of the gunpowder that was used to start the American Revolution. What my Grandmother did not know was there may have been a mystery associated with her ancestor.

See the following link.          http://colonialhall.com/gerry/gerry.php

Elbridge is buried in the Congressional Cemetery , Washington, DC. and was spoken of  in these words.

 "He finally saved the peace of the nation," said the late President Adams, "for he alone discovered and furnished the evidence that X. Y. and Z. were employed by Ta11eyrand; and he alone brought home the direct, formal, and official assurances upon which the subsequent commission proceeded, and peace was made"

Succeeding Adams and Franklin as envoy to France, Gerry was able to resolve the issues our young nation had with France in the early 1800's. But who are X, Y , Z and Ta11eyrand? This is a very interesting quote for a US  president to make don't you think? Why the code?

The kids and I will begin looking into this as part of a home school project this year. If you are a history buff and would like to join us on this adventure we would love to have the help.