All Souls’ Day: November 2nd

All Souls' Day is so called because Catholics on that day seek, by prayer and almsgiving, to alleviate the sufferings of souls in purgatory. It was instituted in the monastery of Cluny in 993.

According to tradition, there was a pilgrim, returning from the Holy Land, who was compelled by a storm to land on a rocky island, where he found a hermit, who told him that among the cliffs was an opening into the infernal regions through which huge flames ascended, and where the groans of the tormented were distinctly audible.

The pilgrim told Odilo, abbot of Cluny, of this, and the abbot appointed the day following, which was the 2nd, to be set apart for the benefit of those souls in purgatory.

What to do on this day? Pray for the souls of all the departed, from your grandparents through to the children of Beslan, say. In this respect, it would mean more than All Hallows to most people and it’s the one I take the most seriously of the three.

All Hallows Eve: October 31st

In the old Celtic calendar, this was the last day of the year, its night being the time when all the witches and warlocks were abroad and held their wicked revels. This was a day NOT to be out.

On the introduction of Christianity, it was taken over as the Eve of All Hallows, or All Saints, and - especially in Scotland and the north of England - it is still devoted to all sorts of games in which the old superstitions can be traced.

Sometimes known as "Hallowmas," many old folklore customs are connected with All-Hallows' Eve, such as bobbing for apples, cracking nuts, finding by various tests whether one's lover is true and so on.

In shortened form, it’s called Hallowe’en [always with the apostrophe]. Burns' Hallowe'en gives a good picture of Scottish customs and there is a tradition in Scotland that those born on All-Hallows' Eve have the gift of double sight, and the ability to command spirits.

Source: Brewers Dictionary of Phrase and Fable