Louis XVI ascended the throne of France in 1774, and his new government in Versailles desperately needed money; the treasury had been drained by the Seven Years' War (1755–63), and the French intervention in the American Revolution would create even more serious financial problems after 1776. In order to raise revenues by charging taxes on merchandise coming into the city, Paris was encircled between 1784 and 1791 by a new wall that stopped merchants who wished to enter Paris. The wall, known as the Wall of the Ferme générale, was twenty-five kilometres long, four to five metres high, and had fifty-six gates at which taxes had to be paid.