hi! not discouraging other (informed) responses, but do check out these posts for previous discussions
Where did the tradition of rulers wearing crowns come from? (Cross-post from /r/AskReddit)
What is the oldest crown we have ever found?
In Greco-Roman and Persian culture (say 1st-4th centuries CE) what were crowns like?
When did crowns become a thing?
Medieval Europe, symbolism of a king's crown - what does it represent, what does it mean to suggest, why the shape?
What made the crown the universal "symbol of kingship" in Medieval Europe?
Why do Dutch and Belgian Monarchs not have crowns?
Did kings wear the crown all the time?