This man agreed to give military support to Nguyễn
This man agreed to give military support to Nguyễn Ánh, an event that would lead to his nation's subsequent interest in Vietnam. This man's status was declared to be "a matter of common interest to all the sovereigns of Europe" in the Declaration of Pillnitz; earlier, riots over the price of bread due to a spectacularly poor harvest undermined his finance minister Jacques Turgot. Under this man's reign, the Estates-General met for the first time since 1614, which resulted in members of the Third Estate signing the Tennis Court Oath. For 10 points, name this monarch who was decapitated during the French Revolution.
This man agreed to give military support to Nguyễn Ánh, an event that would lead to his nation's subsequent interest in Vietnam.
Louis XVI [prompt on Louis]