Both enlightenment ideas and economics link the American and French revolutions. Just as England excited unrest by raising taxes in the colonies to pay for the French and Indian War, so did the French. And King Louis XVI's administration made the situation worse by stretching the French finances even further to support American patriots. Indeed, Louis's generosity made him more vulnerable to the French Revolution of 1789.

That was the year that Louis XVI called a meeting of the Estates-General, the French Parliament, which was a bold move considering the body hadn't met in over150 years. Smart enough to know that things must change, Louis was trying not to lose his crown, and calling the Estates-General into action was an attempt to get agreement on necessary reforms.

But reactivating the organization opened a pressure valve. The idea that the king might permit any reform brought forth a flood of discontent. People were fed up with the privileged class and high taxes. Then on July 14, 1789, an angry mob stormed the Bastille prison, a symbol of arbitrary injustice. Then the Estates-General, under the leadership of some of its more radical members, became the democratic National Assembly, which abolished the monarchy in 1792.

And Louis lost more than his crown: The new government used a French invention — the guillotine — to behead Kind Louis early the next year.