When did Napoleon crown himself emperor?
Coronation of the French monarch
During the First French Empire, Emperor Napoleon I and Empress Josephine were crowned in December 1804 in an extremely elaborate ritual presided over by Pope Pius VII and conducted at the Notre Dame Cathedral in Paris. The pope and prelates entered Notre Dame in procession, followed by Napoleon and Joséphine with the Imperial Regalia preceding them. The regalia were placed on the altar and blessed by the pope, who then seated himself upon a throne to the left of the altar. Following this Napoleon was anointed by the pontiff three times on the head and hands, with the new emperor reportedly yawning several times during this act and the remainder of the ceremony. The high point of the ceremony came when Napoleon advanced to the altar, took the crown and placed it upon his own head. Replacing this with a laurel wreath of gold made in the ancient Roman style, he then crowned his wife, who knelt before him. Six months later, Napoleon was crowned King of Italy at Milan with the Iron Crown of Lombardy.
Constitution of the Year XII
It amended the earlier Constitution of the Year VIII and Constitution of the Year X, establishing the First French Empire with Napoleon Bonaparte — previously First Consul for Life, with wide-ranging powers — as Napoleon I, Emperor of the French. The Constitution established the House of Bonaparte as France's imperial dynasty, making the throne hereditary in Napoleon's family. The Constitution of the Year XII was later itself extensively amended by the Additional Act and definitively abolished with the final return of the Bourbons in 1815.