The Ashtadikpalas are eight in number. As their collective name suggests, they rule the eight quarters or the eight directions of the universe. Ashta means eight, dik means quarters or directions and palas means rulers. According to Hinduism each quarter is assigned to a particular divinity, who presides over it and acts as its chief guardian spirit ensuring the orderliness (rta) of the universe and the protection of its occupants. (It is interesting to note that there are no goddesses in this list, just as there are none in the list of navagrahas also). Symbolically the eight rules of directions are represented as eight elephants standing in eight directions.
The concept of Ashtadikpalas was a post vedic development. In the Vedic period it was the Adityas who ruled the skies and kept a watch over the world from one end to another. The Adityas knew all the deeds, because they had eyes and spies everywhere. The Adityas were born out of Aditi, the mother of all Gods. While the Adityas rule the skies, on earth it is Pusan, the handsome god with a shaft who knew the directions and who shows the paths that lead to green pastures and safe places. In the Rigvedic hymns we do not find any reference to the dikpalas. But as individual gods each of them enjoyed a supreme status and commanded his own following and veneration.
But in the post Vedic period, fundamental changes took place in the Vedic religion. A new order emerged in the Vedic pantheon. Many gods lost their ranks while some completely disappeared. Probably the priests or the priestly families who specialized in their worship and invocation of gods moved elsewhere or turned to new gods. The Rigvedic Aryans migrated from inhospitable terrains to newer and safer lands with a more dependable climate and more hospitable terrain.The emphasis shifted from politics of isolation to politics of adjustment and compromise with native cultures. With the rise of bhakti cults such as Vaishnavism and Saivism, elaborate rituals yielded place to simple devotion to a personal god.The Vedic gods lost their significance during this period and reemerged as the dikpalas.
Images of these gods can be seen in many temples on a central panel in the ceiling of the central pavilion (Mahamandapa) facing the main deity. If the temple is a symbol of God's abode, its ceiling is the sky. The Ashtadikpalas are rightfully the guardians of the sky, watching over us from eight different directions and keeping an eye on all our activities.
The concept of Ashtadikpalas symbolically denotes that God is every where and in every direction and that in whatever direction you proceed or offer your worship, you will ultimately find Him. In ancient times, when one had to travel through difficult terrains or dangerous forests, this belief would have been a great comforter. Many people are perhaps not aware that when we make an atma-pradakshina (revolving around one self) in front of God, we are not only saluting the self with in, the God in front, but also the divinities that are around us in all the directions.