The sacred horse among Celts and Indo-Europeans: Epona, aśvamedha and sun

The horse was perhaps the most important animal in the history of the peoples who spoke Indo-European languages. Language itself bears witness to this: the Sanskrit word aśva, the Latin equus, the Greek hippos and the Old Irish ech all derive from the same reconstructed root. Alongside the word, myths and rites have survived that show the horse as the animal of the king, of the sun and of the passage between worlds.

The sacrifice of the horse

In Vedic India the most solemn royal rite was the aśvamedha, the horse sacrifice, to which the Rigveda devotes two hymns of its first book. According to later ritual texts, a chosen horse was allowed to roam freely for a year, escorted by warriors: the lands it crossed without opposition were considered subject to the king. At the end of the year the animal was sacrificed in a great ceremony.

In Rome there was a rite with some similarities, the October Horse. On 15 October, in the Campus Martius, a chariot race was run and the right-hand horse of the winning team was sacrificed to Mars. According to Festus, the inhabitants of the Subura and those of the Sacred Way then fought over the animal's head. Many scholars have compared these rites with the aśvamedha, despite the obvious differences.

Epona and the horse goddesses of the Celts

In the Celtic world the best-attested deity linked to the horse is Epona, whose name derives from the Gaulish word for horse. She is depicted above all in Gaul and along the Rhine frontier, seated sideways on a mare or between two horses, often with a basket of fruit or a cornucopia. She was very popular among the cavalrymen of the Roman army, and a calendar found in Italy set her festival on 18 December.

The medieval literatures of Ireland and Wales preserve similar figures. In the Welsh Mabinogi Rhiannon first appears on a white horse that no one can catch up with, and later she is condemned to carry visitors on her back like a mare. In Ireland Macha, forced to race against the king's horses while pregnant, wins the race and curses the men of Ulster.

Horses of the sun and of the threshold

In many Indo-European traditions the horse draws the sun. The Trundholm sun chariot, found in a Danish peat bog in 1902 and usually dated to around 1400 BC, shows a bronze horse pulling a disc that is gilded on one side and dark on the other. In the Vedic hymns the sun is sometimes compared to a horse, and the Greeks imagined Helios driving a four-horse chariot across the sky.

The horse was also the companion on journeys to the afterlife. The divine twins, the Aśvins of India and the Greek Dioscuri, are horsemen and rescuers; Odin rides Sleipnir, the eight-legged horse able to descend into the realm of the dead. On the hills of Oxfordshire, in England, the Uffington White Horse, a stylised figure cut into the chalk, dates from the Bronze Age and remains one of the most enigmatic signs of this ancient relationship.

The sacredness of the horse arises from a concrete fact: its domestication changed the way people travelled, fought and governed. The peoples who bred it turned it into a symbol of sovereignty, of the swiftness of the sun and of the threshold between life and death, leaving common traces that stretch from Vedic India to medieval Ireland.