The Apostles’ Creed lists “the communion of saints” among Catholic beliefs, and since at least the ninth century the church has honoured everyone in heaven, including angels, formally recognized martyrs and saints, and all those who had died in God’s friendship, with a November feast.
As early as 411, the Eastern Church celebrated a feast of all martyrs in May.
The custom gradually spread to other regions and included non-martyrs.
In England the feast formerly was known as All Hallows, that is, made holy, which gave rise to Halloween.
Text: Catholic News Service