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. From the 4th century, feasts commemorating all Christian martyrs were held in various places, on various dates near Easter and Pentecost. In the 9th century, some churches in the British Isles began holding the commemoration of all saints on 1 November, and in the 9th century this was extended to the whole Catholic church by Pope Gregory IV. In Western Christianity, it is still celebrated on 1 November by the Roman Catholic Church as well as many Protestant churches, as the Lutheran, Anglican, and Methodist traditions. The Eastern Orthodox Church and associated Eastern Catholic and Eastern Lutheran churches celebrate it on the first Sunday after Pentecost. Source: Duckduckgo API