The coronets (little crowns) illustrated are the designs for the nobility of Great Britain. 

In Great Britain the ranks of the nobility are, in ascending order: Baron, Viscount (Vice Count), Earl (Count), Marquess (Marquis), and Duke.

The Prince of Wales, a title granted to the male heir to the throne by the monarch, has a singular coronet topped with a single arch, in distinction to the double arch of the crown of the monarch.

These coronets demonstrate the hierarchical nature of the nobility.  Other European countries had a similar hierarchy and distinctive headgear for their aristocracy.

Hierarchy is a distinctive characteristic of civil and ecclesiastical society in the period before the French Revolution.  Various writers likened the earthly civil and ecclesiastical hierarchy to the heavenly angelic hierarchy.  Although there are differing arrangements of the angelic hierarchy, that developed by Denys (Dionysius) the Areopagite, d. ca. 500, in his Celestial Hierarchy, is the best known.  Denys arranged the heavenly beings into nine choirs.  The following is a typical arrangement:


  Civil     Church

Seraphim Emperor Pope

Cherubim Kings   Bishops

Thrones Princes     Priests

Dominations Dukes     Deacons

Virtues Marquesses   Subdeacons

Powers   Earls (Counts)   Acolytes

Principalities Viscounts   Exorcists

Archangels     Barons     Lectors

Angels Knights   Porters

Saints   Commons     Tonsured

There were, of course, variations to these equivalencies.  Cardinals, patriarchs, archbishops, archdeacons were allocated with difficulty.  Place was also found, with equal difficulty for Grand Princes, Grand Dukes, Archdukes, and so on.