A tiara (from Persian tara borrowed by latin as "tiara") is a form of a crown. Often referred as a diadem. Traditionally, the word tiara refers to a high crown often with a shape of a cylinder narrowed at its top, made of fabric or leather and richly luxuriant. A diadem (from the Greek 'diadema, diadeo' to surround) was originally a white ribbon that weas placed on the shoulders that surrounded the head of the king.

A Tiara was historically used by kings and emperors of ancient people to denote power and wealth. The Assyrians used to include a pair of bull horns and a circle of feathers as a decoration symbol of authority. This design was modified by the Persians to a more similar truncated cone, without the horns and feathers, with elaborate ornate jewels and a conic shaped tip at the top.
During the birth of Catholicism the Papal tiara was introduced. A high cap surrounded by three crowns and bearing a globe surmounted by a cross. This was worn by the Pope during certain ceremonies bearing the symbol of his authority. Since Pope Paul VI set aside his tiara after the second Vatican Council the Papal Tiara has not been used. Pope Benedict XVI even removed the tiara from his Coat of Arms replacing the symbolism of a mitre.