Initially I must state that for a year now I am seeking to spot a classical resource mentioning and / or even referring the Triesperon festive – in fact there is none and for that reason there is no academic work which discusses Triesperon. There is, therefore, my honest and strong view that the individuals who trust the existence of such festive are seriously mislead. I must, however, state that my intention is not to alter and / or attack any religious feeling and /or practice even if it is contemporary. My pure intention is to make clear the historical veracity for those of interest.
The fact in which we must focus is that the term triesperon was existed in our original classical resources but not as a festivity. There is only appeared as an adjective which was applied to Heracles (tri-esperos, or tri-esperos
Why Heracles was named as Triesperos? According the scholiast, Zeus treis hesperas eis mian metabalon sunekatheude tei Alkmenei (Scholia in Callimachus v.204). It is indeed the mythological incidence of the Heracles’ ‘styled’ by the union of Zeus and Alkmenei. There is therefore no connection with the winter solstice whatsoever.
Where we can find Heracles’ worship? The well-known demos of Cynosarges is extremely connected with Heracles. Heracles’ son, Antiochus, was the eponymous hero of the like-named Antiochid tribe (SEG III 115, 116 and 117). In honour of Heracles there was, in Cynosarges, the religious festive of Heracleia in which He received sacrifices as an Olympian god (Aristophanes, Frogs, 650, SEG 42.50, IG II2 1247, Demosthenes 19.86 and 125, and Suda, eta, 458). There is also a case of Heracles worship at Isthmia were Pausanias located the Gymnasium of Iolaos (9.23, i-ii), where games for Heracles and his sons and to Iolaos entitled Heracleia took place (Schol. n,4.20). Thus, the religious festivities related to Heracles were named after Him as Heracleia in
There is not evidence of when the Heracleia’s feast in Cynosagres was taking place, however, there is a tendency -and assumptions- to believe that Heracles was honored in Attica mainly throughout Metageitnion (July – August) not in November and December (during the winter solstice). On the contrary at the winter solstice, the Attica months of Poseideon (November – December) and Gamelion (December – January) we have a fair number of evidences that suggest that mainly throughout Attica, there were festivities and sacrifices in honour of Poseidon, Hera, and Apollo.
Conclusively we can point out that a) Triesperon as an ancient Greek festivity was never in existence, b) there is no connection in-between Heracles Triesperos and the Heliou genelthion (as explained here) and c) Heracles was not a deity honoured during the winter solstice.
Happy New Year!!