It’s the Feast Day of Saint Michael or Michaelmas.
In the Greek and Roman Catholic Churches, it was once a very important day. It falls near the equinox and so marks the fast darkening of the days in the northern world.
This boundary of what was and what is to be, was the end of the harvest and the time to calculate how many animals could be feed through the winter and which would be sold or slaughtered.
It was the end of the fishing season, the beginning of hunting, the time to pick apples and make cider.
Some people made this a night for a goose dinner, as an old English proverb says: “If you eat goose on Michaelmas Day, you will never want money all the year round.”
Michaelmas (mɪkəlməs) is the feast of Saint Michael the Archangel also knowns as the Feast of Saints Michael, Gabriel, Uriel and Raphael, the Feast of the Archangels, or the Feast of Saint Michael and All Angels.
In Christianity, the Archangel Michael is the greatest of all the Archangels and is honored for defeating Satan in the war in heaven. He is one of the principal angelic warriors, seen as a protector against the dark of night, and the administrator of cosmic intelligence. Michaelmas has also delineated time and seasons for secular purposes as well, particularly in Britain and Ireland as one of the quarter days.
Old Michaelmas Day falls on October 10 or 11, depending on the source, and a according to an old legend, blackberries should not be picked after this date. This is because, so folklore goes, Satan was banished from Heaven on this day, fell into a blackberry bush and cursed the brambles as he fell into them. It is said that the devil had spat or urinated on them.