Background Information:
All Saints Day is an old feast. It arose out of the Christian tradition of celebrating the martyrdom of saints on the anniversary of their martyrdom
4th century AD: Local dioceses instituted a common feast day (as persecutions increased)
373 AD: St. Ephrem the Syrian mentioned it in a sermon
8th century AD: Pope Gregory III (731-741 AD) consecrated a chapel to all martyrs in St. Peter’s Basilica in Rome
9th century AD: Pope Gregory IV (827-844 AD) extend the feast to the entire Church
Final Thoughts: The traditional name for All Saints Day was All Hallows Eve. A hallow was a saint or holy person. So that is how we get the name Halloween (Hallow’s Eve or Hallowe’en).