Multiple realities
(covers information from several alternate timelines)
Garth wearing a crown
Emperor Georgiou wearing her crown
A crown was a piece of headdress usually worn by a monarch.
Some crucifixes depicted Jesus Christ wearing a crown of thorns. (VOY: "The Omega Directive")
An important Klingon artifact was the Emperor's Crown. (DS9: "The Sword of Kahless")
In 2268, Garth of Izar performed his own coronation as "Master of the Universe", which included a crown. According to Garth the crown wasn't impressive by itself, but would act as a symbol around which his followers could rally. (TOS: "Whom Gods Destroy")
Sometime prior to 2369, Vash stole the Crown of the First Mother from the planet Myrmidon. (DS9: "Q-Less")
The kings and queens of Hysperia wore crowns. (LD: "Where Pleasant Fountains Lie")