Halo or nimbus has had numerous symbolic meanings such as political power, moral power, and spirituality in the iconography of numerous cultures that are Christian, Egyptian, Islamic, Buddhist and Hindu art. It functions as a kind of crown that separates the person wearing the halo from the others through the use of light symbolism. So, where does this universal motif come from? The origins of halo go back to paganism.
Many scholars put forward the idea that it comes from the Greek sun god Helios whose golden crown emits light beams, and it originally symbolize power rather than divinity.
Scholars suggest Helios because he is a figure that has Indo-European origins, and he is the reflection of Ra in Egyptian mythology, the patron god Baal in Phoenician pantheon and also has a connection to Mithra.
Persian miniature depicting Muhammad, Abraham, Moses, and Jesus
Ra (before 1235 BC)
The Mughal Emperor Jahangir
In the East, halo generally symbolizes physical and moral power as well as political and religious authority. As for the West, Romans kept on using halo after ancient Greek. For example, they depicted past emperors wearing halo on coins. It was also a way of propoganda by connecting the emperor to the sun god to provide royal lineage.
A Standing Budha from 1ts- 2nd Century AD
Ptolemy III who was the Egyptian pharaoh between 246-222 BC
It became prevalent among Christians to use hale in the 6th century. At first, they were hesitant to use halo as a symbol of spirituality because it was a pagan element. Moreover, they depicted satan wearing a halo (generally black in color) in the early Byzantine art.
Mosaic of Justinian I in the Basilica of San Vitale
Over time, nimbus changed shape and size. The circular one is for god, apostles, and saints. Square is for the people who were alive at the time and worthy to become a saint after they died. There are also triangle halos for the holy Trinity. Although it is rare, hexagonal halos are also used in Italian art for allegorical figures.