Napoleon dreamed of building a French economic sphere in Latin America, centered on Mexico. He helped to rapidly promote rapid economic modernisation, but his army battled diehard insurgents who had American support. By 1863, French military intervention in Mexico to set up a Second Mexican Empire headed by Emperor Maximilian, brother of Franz Joseph I of Austria, was a complete fiasco. The Mexicans fought back and after defeating the Confederacy the U.S. demanded the French withdraw from Mexico—sending 50,000 veteran combat troops to the border to ram the point home. The French army went home; the puppet emperor did not leave and was executed.