Halo is a circle of light that is shown in religious art as surrounding the head of an enlightened or Godly being. It is also known as Aureole, Nimbus, Gloriole and Glory. The symbol represents the radiant aura that is all around pious and saintly persons. So, it has become representative of divinity, supreme power and sacredness. The Halo can be depicted in almost any color. However, since it represents light, it is usually shown as white, yellow, golden or red. In all probability, the practice of using the Halo with deities is the result of identifying the divine beings with the Sun.
As a holy symbol, the Halo is not restricted to any particular religion or culture and halos have been extensively used to depict holiness especially in the Christian, Islamic, Hindu and Buddhist religious images. Halos have been seen in the ancient Greek and Roman art which is likely to have influenced its use in the Christian art. The Halo is closely associated with the Christian symbol of Circle, which represents eternity. The Christians considered the circle as divine since several of God's creations such as the sun, moon and planets were circular. The halo came to be connected with the luminous circle around the moon and sun.
In the Asian art such as the Chinese bronzes, the Halo is often shown not merely as light, but as consisting of flames. The symbol has been widely used in Indian art, especially the Buddhist iconography and Hindu sculptures. Japanese and Chinese Buddhist art have long used the halo in images of Amitabha Buddha. Tibetan Buddhism has also used it a lot in statues and the Thangka paintings of deities and saints.
The Halo has appeared in the Islamic art as well, specifically in Moghul art and Persian miniatures.