Diadem

A diadem (from Greek 'diadema, diadeo', to surround) was originally a white ribbon, ending in a knot and two stripes that were placed often on the shoulders, that surrounded the head of the king to denote his authority.

By extension, this term was applied later to a crown, generally with a circular shape. For example, the crown worn by a Pagan drihten (Anglo-Saxon king) was a diadem, as was the crown of a baron later (in some countries surmounted by three globes).

A diadem is also a jewelled ornament worn by women with the shape of a half crown, placed over the forehead (in this sense, also called tiara). In some societies it is also a wreath worn around the head.