Ashvamedha, or horse sacrifice, was one of the main royal sacrifices in ancient India, performed to enhance the power and glory of the king. Naturally, it was the ambition of every king to conduct this sacrifice, though it can be performed only by the mighty monarchs. Apart from glorifying the king, the rite also was instrumental in bringing the prosperity and fertility to the kingdom.
As the name suggests, a stallion marked with king's name was set free to wander at will for a year. The rulers and the chieftains of the territories on which the horse, followed by a chosen bans of warriors, roamed had to either accept the suzerainty of the king or defeat the accompanying warriors in the battle.
When after a period of one year the horse returned to the kingdom accompanied by the kings of the territories where it entered, it was sacrificed. Sometimes scores of other animals were sacrificed with the horse. This elaborate sacrificial ritual, participated in by the priest, the king and the queen, was held at a great public ceremony characterized by celebration and feasting. During the ceremony, the queen had to spend one night near the dead horse.
The ritual has been described at great length in several texts, chief among them being the Shatapatha Brahmana, a text on sacrificial ritual. An interesting element in the rite was that during the ceremony, the queen had to spend one night beside the dead stallion.
Pushyamitra Sunga, the founder of the Sunga dynasty, performed this sacrifice after usurping the Mauryan throne signaling the restoration of the Vedic sacrificial rituals which went into disuse during the Mauryan period. Samudra Gupta and Kumara Gupta (c 415-454) of the Gupta dynasty, the golden period of Hinduism, performed this sacrifice. Adityasena Gupta of the second Gupta dynasty performed this sacrifice in the latter half of the 7th century AD. After the Gupta period, the horse sacrifice became rare and the last famous instance of this sacrifice was that was performed in the mighty south Indian empire of the Cholas.