When did tiaras become fashionable, and do you have to be royal or of aristocratic birth to wear one?
In ancient Greece garland-like hair ornaments were used to adorn the heads of sacred statues, given to athletes and warriors to honor victories, and worn by people of high rank at weddings and feasts. These early examples often took the form of gold bands, also known as fillets, or naturalistic foliate wreaths composed of ears of wheat, laurel leaves and flowers. The Romans continued the Greek tradition, but with the eventual demise of their world and the rise of Christianity, the wearing of classical wreaths and diadems declined and almost disappeared.
In the Medieval period crown-shaped jewels, or coronals, were worn by brides of all ranks, but it wasn’t until the 18th century that tiaras as we might know them today became more widely worn. This was probably due to advances in the cutting of gemstones — head ornaments became less the concern of goldsmiths and more the preserve of lapidaries for showing off their gem-setting skills. Relatively simple gold jewels made way for highly impactful and elaborate diamond and colored stone-set examples.