Napoleon Crowns himself King of Italy

"...Upon the llth April, Napoleon, with his Empress, set off to go through the form of coronation, as King of Italy. The ceremony almost exactly resembled that by which he had been inaugurated Emperor. The ministry of the Pope, however, was not employed on this second occasion, although, as Pius VII. was then on his return to Rome, he could scarcely have declined officiating, if he had been requested, by Buonaparte to take Milan in his route for that purpose. Perhaps it was thought too harsh to exact from the Pontiff the consecration of a King of Italy, whose very title implied a possibility that his dominion might be one day extended, so as to include the patrimony of Saint Peter. Perhaps, and we rather believe it was the case, some cause of dissatisfaction had already occurred betwixt Napoleon and Pius VII. However this may be, the ministry of the Archbishop of Milan was held sufficient for the occasion, and it was he who blessed the celebrated iron crown said to have girded the brows of the ancient Kings of the Lombards. Buonaparte, as in the ceremony at Paris, placed the ancient emblem on his head with his own hands, assuming and repeating aloud the haughty motto attached to it by its ancient owners, Dieu me I'a donne; Gare qui la touche.* ..."



`•God has given it me; Let him beware who would touch it


From Scott's "The Life of Napoleon..."
 
On May 23, 1805, Napoleon Buonaparte crowned himself with the iron crown of the Lombards.  This crown contains an inner band of sacred iron, said to have been made of one of the nails used in Christ's crucifixion.  Napoleon thus joined such rulers as Charlemagne, Otto I, and Henry IV in having been anointed ruler with the Iron Crown.