An Agonalia or Agonia was an obscure archaic religious observance celebrated in ancient Rome several times a year, in honor of various divinities.
[citation needed] The presiding priest was the rex sacrificulus, and the site was the Regia, both of which could be employed only for ceremonies connected with the highest gods that affected the wellbeing of the whole state.
The Circus Agonensis, as it is called, is supposed by some to have occupied the place of the present Piazza Navona, and to have been built by the emperor Alexander Severus on the spot where the victims were sacrificed at the Agonalia.
[5] In Ovid's poem on the Roman calendar, he calls it once the dies agonalis ("agonal day")[6] and elsewhere the Agonalia,[7] and offers a number of etymologies of varied plausibility.
This third occurrence of the Agonia or Agonalia shares the date of December 11 with the Septimontium or Septimontiale sacrum, which only very late Roman calendars take note of and which depends on a textual conjecture.