Before it became the world's most visited museum, the Louvre was the royal residence of the Kings of France. It began as a medieval fortress built by Philip Augustus around 1190. In the mid-16th century, Francis I began transforming the fortress into a Renaissance palace. Subsequent monarchs, including Henry IV and Louis XIII, continued to expand and adorn it. The most famous residents were the members of the French royal court until Louis XIV moved his primary residence to the Palace of Versailles in 1682. Even after the court moved, artists and academies lived and worked within its walls. During the Napoleonic era, Napoleon Bonaparte also used the Louvre as a palace and a place to showcase his war trophies. It wasn't until the French Revolution that the National Assembly decreed the Louvre should be a museum to display the nation's masterpieces, finally opening to the public in 1793.