The name "France" derives from the invasion and conquest of Roman Gaul by Germanic tribes known as the Franks. By 486 A.D., these tribes united under a monarchy that replaced the Roman administration. By the 8th century, the Frankish empire of Charles the Great was divided by his sons into many kingdoms, two of which are modern-day France and Germany. From the 5th century to the late 18th century, France was a monarchy.
In 1789, the Bourbon dynasty was overthrown, and in 1792 it was replaced by a republic. The writings of Jean-Jacques Rousseau were particularly influential with French revolutionaries. Many countries attacked the new republic for its execution of Louis XVI and its revolutionary aggression. France became highly militarized under Napoleon Bonaparte, who eventually declared himself emperor. After the defeat of Napoleon, a succession of republics and of restored Bourbon and Bonapartist monarchies alternated until the Fifth French Republic was finally established in 1958.