A celebration on the first of November instituted to honour all the saints, known and unknown; and according to Urban IV, as pennence to deficiencies in the faithful's celebration of saints' feasts during the year.
In the same vein as the United States Memorial Day, All Saints' day is meant as a bulk celebration of all those who have served the church but who have not been recognized or canonized. Another legend also says it was alos used as a 'cleansing' from evils of All Hallow's Eve, which occurs the day before (October 31 in the modern calendar).