All Saints' Day is a Christian holy day observed by many Western churches on November 1 and by Eastern churches on the first Sunday after Pentecost. The day now honors all saints of the church, even those not known by name.
All Saints' Day was a solemn religious occasion. It was also referred to as "All Hallows Day". Like the Tuesday before Ash Wednesday and the beginning of Lent, the evening before All Hallows became a time for getting your partying in before you had to be all sober-sides. Elements of the pagan Samhain celebrations of the same day also crept into the evening festivities before All Hallows.
All Souls' Day, November 2, is a Christian holy day commemorating all who have died while a faithful member of the church. This is the day of gravesite visits and feasting in the Mexican Days of the Dead.