Crown of Dragons

A symbol of the power entrusted to the royal family of the Empire of Timara from Tiamat herself, it is the most prized possession by the King and Queen. The crown itself is made from gold and has 5 spikes that rise from the base of the crown. The crown has 5 gems embedded each one a different kind. A ruby, sapphire, pearl, emerald, and onyx of exceptional quality and clarity adorn the crown-making anyone who sees it become entranced by its beauty. 
The crown itself is said to be gifted to the first king of Timara by Tiamat herself as a sign of her trust in the king to rule the land and carry her name to the far reaches of the land. Any dragon of Tiamat's brood who sees the crown acknowledge the will of their mother, and queen and pledge their service to the Empire. This is as its told throughout the Empire.
This is not the whole story, but elements of the truth twisted by time. The crown indeed was gifted by Tiamat to the first king of Timara but the gems themselves store a bit of her divine essence. This allows the one who wears the crown to exert control over any dragon that comes from the bloodline of Tiamat often against the creature's will until they submit to the will of the king and ultimately the Empire. The crown is bound to the bloodline of the royal family and its magic can only be used by them.
This powerful artifact mimics another set of powerful artifacts known as Orbs of Dragonkind. There are only a few outside of the royal family that know this secret and guard it jealously knowing that powerful dragon army might just turn against them if the crown was ever lost or worse, destroyed.