Festival of purification
The Poitropia festival was an annual event that occurred during the winter month of Poitropios. While its exact date is uncertain, it is believed to have been a purification ritual, and may have been associated with the worship of Dionysos, Apollon and/or Zeus. The festival included award ceremonies and the granting of public honors, as evidenced by an inscription honoring Aristodama.
In the month of Poitropios. Exact day is unknown, but the 9th has been selected in honour of Dionysos, who rules Delphi in the winter.
While not much is known about the specific details of the festival, its name suggests its association with purification rites. A similar festival called Prostrope is mentioned in a list of festivals from Thasos. The festival was linked to award ceremonies and the bestowing of public honours, as indicated by the Inscription from Chaleion honoring Aristodama.
The related epithet "Prostropaios" may be associated with Zeus and/or Apollon, both of whom are sometimes known as "Apotropaioi" $^{5}$. This epithet would apply to these gods in their roles of purification, protectors and averters of evil. Dionysos has epithets related to purification, such as Katharsios (Καθάρσιος - purified one), Liknitês (Λικνίτης - of the winnowing basket), & Agnós (ἁγνός - holy/pure) and may have been offered to at this winter festival - the time of year when Dionysos is said to have ruled in Delphi.
The líknon (of Liknitês) acts as a sieve in the separation of wheat from the chaff compared by Servius (below) to the purification of the soul. The consecrator at Delphi (hosioter/ὁσιωτὴρ - a word that could also be translated as “purifier”) is a bull, an animal heavily connected to Dionysos, and the 5 priests called hosios/ὅσιος are involved his mysteries (Plutarch, The Greek Questions). The exact date of the festival is unknown, but the ninth day of the month is frequently assoicated with Dionysos, and in the 5th century BCE the moon appears near the constellation of the Bull (Taurus) on this date in Delphi.
The mystic fan of Iacchus, that is the sieve of the threshing-floor. He calls it the mystic fan of Iacchus, because the rites of Father Liber had reference to the purification of the soul, and men are purified in his mysteries as grain is purified by fans. It is because of this that Isis is said to have placed the limbs of Osiris, when they had been torn to pieces by Typhon, on a sieve, for Father Liber is the same person, he in whose mysteries the fan plays a part, because, as we said, it purifies souls. Whence also he is called Liber, because he liberates, and it is he who Orpheus said was torn asunder by the Giants. Some add that Father Liber was called by the Greeks Liknites. Moreover the fan is called by them liknon, in which he is currently said to be placed after he was born from his mother's womb. Others explain its being called 'mystic' by saying that the fan is a large wicker vessel in which peasants, because it was of large size, used to heap their first-fruits and consecrate it to Liber and Libera. Hence it is called ' mystic'.
– **Maurus Servius Honoratus, *Commentary on the Georgics of Vergil, 1.166** Translation from Mystica Vannus Iacchi, Jane E. Harrison https://www.jstor.org/stable/623794*
It is resolved [to praise her] for the piety that she has towards [the god], and [on account of] her goodwill towards our city, [and] to crown her [with a crown] of the god's sacred laurel, as is traditional [for the Chaleians]. [The sacred herald] shall announce the award in the festival of Poitropia. A portion [of meat] from the sacrifice for Apollo shall be [sent] to her as a gift of honour from [our city, 20 for feasting at] Smyrna.
– *Chaleion honours Aristodama of Smyrna, 218/7 B.C.$^{92}$*