'All Saints Day' is celebrated on November 1st. All Souls Day is November 2nd. During the eighth century the Catholic Church designated the first day of November as 'All Saints Day' ('All Hallows') - a day of commemoration for those Saints that did not have a specific day of remembrance. 

The All Saints' Day celebration was also called All-hallows or All-hallowmas (from Middle English Alholowmesse meaning All Saints' Day) and the night before it, the traditional night of Samhain in the Celtic religion, began to be called All-Hallows Eve and, eventually, Halloween.