All Hallow’s Eve, or Halloween, is the vigil of All Saints (All Hallows) Day, which is a major feast on the liturgical calendar and a Holy Day of Obligation. Halloween (October 31st) is connected with All Saints Day (November 1st) and All Souls Day (November 2nd). These three days are the “Days of the Dead,” a triduum also known as Allhallowtide or Hallowmas, reminding the faithful of the reality of heaven and hell; the communion of saints; and our obligation to pray for the Holy Souls in Purgatory.