Imperial crown

... the closed crown, which had bands of metal crossing usually from one side to the other and from back to front so that they met in the middle, at the top of the head.

This was originally an open crown, made up of eight separate richly jewelled sections incorporating four magnificent enamelled plaques, but the Emperor Conrad II (1024–39) had added to it a kind of jewelled crest, running from front to back, to which he had thoughtfully attached his name, CHVONRADVS DEI GRATIA ROMANORV(M) IMPERATOR AVG(VSTVS).

This jewelled crest was so closely associated with the notion of the imperial office that when the Habsburgs made a new imperial crown in the 15th century in which they incorporated two large cusps resembling a mitre seen sideways, they provided it with a similar crest running from front to back and topped with a central jewel.

Strictly speaking, therefore, the only type of crown whose characteristics can properly be regarded as imperial was one with a single crest running from front to back.

For example, Henry V of England wore a helmet-crown of the arched type at the Battle of Agincourt which the French knight St. Remy commented was "like the imperial crown".

A miniature picture in the Chronica Aulae Regiae written in the great abbey outside Prague depicts his mother Elizabeth, a queen of Bohemia, wearing an open crown, while his two wives, who had imperial titles, have closed ones.