October Horse: An Introduction


The festival takes place on 15th October (the Ides of October: Id. Oct). The day is known as Feriae Iovi, with the name Equus October only given in the late Calendar of Philocas.

Proceedings in order

  • A two-horse chariot-race takes place
  • The right-hand horse of the victorious pair is felled with a spear and sacrificed on the altar to Mars in the Campus Martius (“Plain of Mars”)
  • The horse’s head is cut off and decorated with loaves
  • The inhabitants of the Via Sacra contend with those of the Suburra to claim this trophy. If those from the Via Sacra win the horse’s head, they nail it to the Regia; if those from the Suburra, it is fixed to the Turris Mamilia.
  • The horse’s tail, dripping with blood, is brought quickly to the Regia and is allowed to fall on the sacred hearth.

1st century B.C. Historical Impact

In 44 BC, Caesar handed over two mutinous soldiers to the flamen Martialis who killed them in the Campus Martius and had their heads fixed on the Regia – was this a grim civil-war version of the October Horse? (Dio 43.24.4)

Controversies and Opinions 

What was the origin of the festival? 

  • Was it agricultural, the last in series of harvest festivals?
  • Was it military, owing to the sacrifice to Mars, its proximity to the end of summer campaigning season and the Armilustrium (19 October) and th echo of the horse race (Equirria, 14 March), which marked the beginning of the campaign season?
  • Or did an agricultural festival develop into a military festival over time, in the same way that Mars, god of war, is thought to have started life as an agrarian deity?
  • Was the festival influenced by a royal Vedic (Indian) ritual? Is this a royal battle between two groups of pretenders, the king (those who take the trophy to the Regia) and the Mamilii (historical claim to an emblem of kingship?)

Why a horse? Does it symbolise the Trojan Horse, making the festival a revenge ritual in which the Romans (descended from the Trojans) take revenge on the Greeks who destroyed their mother city? Or is the horse a warlike and spirited animal that is sacrificed for a like-minded (military) deity?

What sort of horse is sacrificed? Is it an agricultural animal? Or a military one?

Is the flamen Martialis involved in the ritual at all?

Does the spear actually kill the horse, and who wields it?

Is the blood of the October horse used at the Parilia the following April? No ancient source states this, but we are only told that the Parilia uses the blood of a horse (origin unspecified). But isn’t it too much of a coincidence, given that no other horse is sacrificed in Roman religion?

Did the blood really drip, or put another way, is the tail really a tail? There are physical problems to consider here, as by the time a horse’s tail would have arrived at the Regia, the blood would have coagulated (clotted). This means it would have been very difficult to arrive at the Regia with a ‘dripping tail’. If ‘tail’ in our sources is really a euphemism for the horse’s penis/genitals, which contain a lot of blood, these could still feasibly be dripping blood on arrival at the Regia.

What was the Turris Mamilia? The identity of this building is unknown. The Mamilii are said to have given their name to it; they were originally Tusculans but might claim links with Roman royalty through a connection to the Tarquins.

Are elements of the festival vested with magical properties (such as the spear and the decapitation)?

Major Ancient Testimony

CASSIUS DIO, 43.24.4

PAULUS, p. 197, 326 Lindsay


PLUTARCH, Roman Questions, 97

FESTUS, pp. 190, 246, 295-6 Lindsay

[The obscure primary sources are conveniently located and translated in Dumézil (1970) 215-16 and Bennett Pascal (1981) 261]

Secondary Reading

C. Bennett Pascal (1981), “October horse”, Harvard Studies in Classical Philology 85, 261-91

G. Devereux (1970), “The equus October ritual reconsidered”, Mnemosyne 23, 297-301

G. Dumézil (1970), Archaic Roman Religion, Chicago, 213-28

H.H. Scullard (1981), Festivals and Ceremonies of the Roman Republic,New York, 193-4