A diadem is a type of crown, specifically an ornamental headband worn by monarchs and others as a badge of royalty.
Coin of Antiochus III the Great of the Seleucid Empire, shown wearing a diadem; the Greek inscription reads ΒΑΣΙΛΕΩΣ ΑΝΤΙΟΧΟΥ, of King Antiochus.
Gold diadem. India, 9th–10th century
The diadem or crown of Princess Sit-Hathor Yunet from her tomb. 12th Dynasty Egypt 19th century BC.
17th Dynasty diadem crown (Rijksmuseum van Oudheden)
A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, particularly in Commonwealth countries, as an abstract name for the monarchy itself, as distinct from the individual who inhabits it. A specific type of crown is employed in heraldry under strict rules. Indeed, some monarchies never had a physical crown, just a heraldic representation, as in the constitutional kingdom of Belgium.
Imperial Crown of Kingdom of Sicily (Crown of Constance of Aragon, Cathedral of Palermo).
Imperial Crown (Benkan) of Emperor Kōmei of Japan
Imperial Crown of Austria
Imperial Crown of Russia, 2012 replica
