Crowns

In the Christian tradition of European cultures, where ecclesiastical sanction authenticates monarchic power, when a new monarch assumes the throne in a coronation ceremony, the crown is placed on the new monarch's head by a religious official. Some, though not all early Holy Roman Emperors travelled to Rome at some point in their careers to be crowned by the pope. Napoleon, according to legend, surprised Pius VII when he reached out and crowned himself, although in reality this order of ceremony had been pre-arranged (coronation).
Today, only the British Monarchy and Tongan Monarchy continue this tradition as the only remaining anointed and crowned monarchs, though many monarchies retain a crown as a national symbol in heraldry. The French Crown Jewels were sold in 1885 on the orders of the Third French Republic, with only a token number, with their precious stones replaced by glass, held on to for historic reasons and displayed by the Louvre. The Spanish Crown Jewels were destroyed in a major fire in the eighteenth century while the Irish Crown Jewels (actually merely the Sovereign's insignia of the Most Illustrious Order of St Patrick) were stolen from Dublin Castle in 1907.
Special headgear to designate rulers dates back to pre-history, and is found in many separate civilizations around the globe. Commonly, rare and precious materials are incorporated into the crown, but that is only essential for the notion of crown jewels. Gold and precious jewels are common in western and oriental crowns. In the Native American civilizations of the Pre-Columbian New World, rare feathers, such as that of the quetzal, often decorated crowns; so too in Polynesia (e.g. Hawaii).
• Coronation is often combined with other rituals, such as enthronement (the throne is as much a symbol of monarchy as the crown) and anointing (again religious sanction, the only defining act in the Biblical tradition of Israel).