Samhain was later transformed as Christian leaders co-opted pagan holidays. In the seventh century Pope Boniface IV decreed November 1 All Saints' Day, or All Hallows' Day.

Halloween is not celebrated in many countries and regions of the world and among those that do the traditions and importance of the celebration vary significantly.

There are several games traditionally associated with Halloween parties. One common game is dunking or apple bobbing, in which apples float in a tub or a large basin of water and the participants must use their teeth to remove an apple from the basin.

The term Halloween (also spelled Hallowe'en) is shortened from All Hallows' Even – e'en is a shortening of even, which is the origin of the words "evening" and "eve". This is ultimately derived from the Old English Eallra Hālgena ǣfen. It is now known as "Eve of" All Saints' Day,[citation needed] which is November 1st.