However, only Vattel defines "Natural Born Citizen." There was simply no other source (known) from where they could have gotten that term defined from.
DECLARATION OF INDEPENDENCE (1776)
"In composing this greatest, most famous of legal documents, Jefferson, already well regarded as an essayist, drew heavily not only on the ideas of his fellow patriots, but also on the natural-rights theories of John Locke and the Swiss legal philosophy of Emerich de Vattel."
I’m just amazed that anyone would think that, of all the laws of the country they were fighting to separate from, the law governing who was a royal subject would have anything to do with anything, in this constitutional republic they were struggling to create. Sam Adams was citing Vattel in 1764, regarding constitutional primacy over parliament, for goodness sake.