General form of the records
Generally, the records take the form of the bureaucrat recording what happened in his office. First, he writes the current date, and often the time (alle ore) when somebody strolled on into the joint. In the case of death records, he would record, often in considerable detail, the identities of the two men who made the trip to town hall (Casa comunale) to declare. These men are the declarants (dichiaranti) in the record. The bureaucrat does not record that Antonia Scaramella died last night, because he was not there to see it happen. He records that the men declared that Antonia Scaramella died last night.
Birth records normally record the name of the father as the declarant, because he proudly presented the baby. In some cases, a midwife (levatrice) brings in the baby, especially on behalf of a single mom. In other cases, the mother brings in the baby because the father is not available.
Marriage records take the form of the bureaucrat recording the date and time when the groom and bride are personally present (sono comparsi) before him.
Some of these documents record an actual civil marriage taking place in the town hall. The parties might then go to a church for a sacramental marriage. Other documents record a solemn promise to celebrate the marriage before the church according to the form prescribed in the Sacred Council of Trent. These usually include a notation saying when and in which parish the sacramental marriage happened. Read these carefully. The document might start out saying that on a certain date, town hall received back an annotated copy of a solemn promise to marry, on which is is stated that the marriage happened on a certain date. You are seeking the date when the groom and bride married, not necessarily the same date that the bureaucrat received the notice.