Public announcements of an intended marriage. Their purpose is to discover matrimonial impediments if any exist. Unless a dispensation has been secured, three publications are required on three Sundays or holy days in the churches of the marrying parties. Anyone knowing of such impediments is bound in conscience to make the same known to the clergy concerned. Similar announcements are required for those about to receive holy orders. (Etym. Anglo-Saxon gebann, a proclamation.)
Cann 645.1 mandates that the candidate shows proof of his baptism, confirmation and free status. The first two can be proved by the relevant certificates issued by the church where he received those sacraments. But what about free status and non encumbrance? Does any parish issue certificates in those cases where civil laws come into play? In most cases, affidavits filed by the person himself and duly attested by a designated authority serve the purpose. But, seminaries are not known to have been obtaining affidavits from the aspirants or novices. Instead, they talk to the priests of the parish to which the aspirant or novice originally belongs, to make sure that none of the impediments are attracted in his case. The publication of Banns is definitely a good concept. It however needs to be done in the parish to which the aspirant or novice belongs.