The announcement of wedding banns were required before a couple could be married. For this purpose, the promulgation books (liber promulgationum sponsorum, liber publicationum, liber bannorum, Eheverkündigungsbuch, Brautleute) were maintained. They contain chronological entries of upcoming weddings, including the names of the betrothed, their residences, family status, age & occupation as well as their parents, and finally three terms of performed banns. The planned wedding was announced in the church by reading the entry from the promulgation book at the end of Mass. The announcement of these banns was made on three consecutive Holy Days in the parish church(es) of both the groom and bride. Parishioners were obliged to inform the priest of any canonical impediment to that marriage if they were aware of any.

Books of banns can be very useful when the parish registers are missing or unavailable. They can also be very helpful if we need to identify the place of a marriage that took place out of the ancestral village.