As a non-Roman Catholic, I was stunned by the annulment petition a friend had his diocese send me as a witness. Later when I met with a priest, I was a bit amused by his take on Massachusetts marriage history.
The couple had been married for 30 years and had four kids. I was supposed to be a witness because I knew them when they were dating and could say they didn't know what they were doing when the married. To get to that required 72 essay questions, including what I knew of their sex lives.
When I filled in what I could, I was supposed to have a priest witness my witnessing. It's not that the investigator in Savannah didn't trust guys in trousers, but a priest would be better. Well, it's no problem finding a priest in Boston and I made an appointment with the (honest to God) Father Francis Kelley, the pastor.
He pored over the questions and answers with what seemed more than professional interest. When he found that I was not RC, he happily interpreted the process, and explained that different bishoprics used their own, generally shorter, forms. He is an investigator for Boston for annulments.
Then he held forth on the history of marriages in Massachusetts, claiming that the priests kept the records for a long time before the government took over. He wasn't aware that clerics were forbidden to marry couples here in colonial times. Of course, there weren't many Catholics in the area to pass along the oral history either. (The first New England Catholic church started in Boston in 1788, a century and one-half after the Puritans got there, though priests had visited before.)
While parishes did keep their records, before there were parishes, towns with formal governments kept their own. Of course, farming families maintained their own records in Bibles. I do like Father Kelley's image of the priests keeping ancestral continuity through records. It's not accurate in the main, but it is comforting.