Many ethnic religions from Indo-European speaking peoples show evidence for horse sacrifice, and comparative mythology suggests that they derive from a purported Proto-Indo-European ritual and common root, though the practice is also observed among non-Indo-European speaking peoples, especially in nomadic societies from the Eurasian steppe.
[1] The Indian Aśvamedha is the clearest evidence preserved, but vestiges from Latin and Celtic traditions allow the reconstruction of a few common attributes.
Some scholars, including Edgar Polomé, regard the reconstruction of a purported common Proto-Indo-European ritual as unjustified due to the difference between the attested traditions.
But if the horse stayed alive for a year then it was taken back to the king's court where it was bathed, consecrated with butter, decorated with golden ornaments and then sacrificed.
[3] The Roman Equus October ceremony involved:[10] Following the 12th-century Anglo-Norman invasion of Ireland, Norman writer Gerald of Wales wrote in his Topographia Hibernica that the Irish kings of Tyrconnell were inaugurated with a horse sacrifice.
[15][16] This is consistent with archaeological finds dating to the Early Medieval Period from England and Scandinavia showing deposits of horses that have been eaten.