The banns of marriage, commonly known simply as the "banns" or "bans" /bænz/ (from a Middle English word meaning "proclamation", rooted in Frankish and from there to Old French), are the public announcement in a Christian parish church or in the town council of an impending marriage between two specified persons. It is commonly associated with the Catholic Church and the Church of England and with other denominations whose traditions are similar; in 1983, the Roman Catholic Church removed the requirement for banns and left it to individual national conferences of bishops to decide whether to continue this practice, but in most Catholic countries the banns are still published.
The purpose of banns is to enable anyone to raise any canonical or civil legal impediment to the marriage, so as to prevent marriages that are invalid. Impediments vary between legal jurisdictions, but would normally include a pre-existing marriage that has been neither dissolved nor annulled, a vow of celibacy, lack of consent, or the couple's being related within the prohibited degrees of kinship.
Banns is related to ban.
The original Catholic Canon law on the subject, intended to prevent clandestine marriages, was decreed in Canon 51 of the Lateran IV Council in 1215; until then, the public announcement in church of marriages to be contracted was only made in some areas. The Council of Trent on 11 November 1563 (Sess. XXIV, De ref. matr., c. i) made the provisions more precise: before the celebration of any marriage, the names of the contracting parties should be announced publicly in the church during Mass, by the parish priests of both parties on three consecutive Holy Days. Although the requirement was straightforward in canon law, complications sometimes arose in a marriage between a Catholic and a non-Catholic, when one of the parties to the marriage did not have a home parish in the Roman Catholic Church.