#attic calendar hekate

Τριακάς - From today’s sunset: Ἑκάτης δεῖπνον. The end of the Month, the Old and New - it is always sacred to the Goddess Hekate.
https://www.academia.edu/11144029/Hekate_cenni_teologici_e_culto

“the thirtieth we celebrate in Hades because of Hekate” - ie , the thirtieth day of the month (if present, otherwise the 29th, which is, in any case, called ‘thirtieth’) is honored Hekate as it is the last day of the month and at the same time, we also honor the dead (in fact, in its calendar, Pletho dedicated the twenty-ninth day to Pluto).
“The image of Hekate is erected and consecrated at the crossroads, and rites in honor of the dead have been made on the thirtieth day.”
The last day of the month must be also devoted to meditation and to the reconsideration of the work done during the month, as well as to the preparation for the new month to come. In any case, no one should undertake an important work during this last day. It is highly recommended to fast for the whole day (for example, this was the habit of Proklos)

(Detail of a marble statue of Hekate. First century CE. Now in the Rijksmuseum van Oudheden - Leiden…)