All Saints Day

This is the day when all the saints are honored, especially those who do not have a day of their own. Following the triumph of the Holy Roman Empire over Celt-occupied lands in the 1st century A.D., the Romans incorporated many of the Celtic traditions, including Samhain, from which the holiday Halloween developed.

Eight hundred years later, the Roman Catholic Church further modified Samhain, designating November 1 as All Saints’ Day.The day was formerly known as Allhallowmas, hallow meaning to sanctify or make holy. All Saints’ Day is known in England as All Hallows’ Day, and the evening before is All Hallows’ Eve, the origin of the American word “Halloween.”

Source: Almanac.com