All Saints' Day, also known as All Hallows' Day, the Feast of All Saints, the Feast of All Hallows, the Solemnity of All Saints, and Hallowmas, is a Christian solemnity celebrated in honour of all the saints of the Church, whether they are known or unknown.

In some strains of Christian theology, the Christian Church may be divided into:the Church Militant, also called the Church Pilgrim, which consists of Christians on Earth who struggle as soldiers of Christ against sin, the devil, and "the rulers of the world of this darkness, against the spirits of wickedness in the high places"; the Church Penitent, also called the Church Suffering or the Church Expectant, which in the theology of certain churches, especially that of the Catholic Church, consists of those Christians currently in Purgatory; and the Church Triumphant, which consists of those who have the beatific vision and are in Heaven.