Let me start with the Quackenburg Church Register.
Back in the old days when a person is born, married, or dies a record is kept by the town mayor or some official in that town. Once a year or so the traveling church representative would come by and record all the information in the church register being it Lutheran, Baptist, or Catholic etc.
When my relatives moved from where ever they lived (haven't found that place yet, but I'm thinking Poland based on Great Uncle Herman speaking High German [a refined type of German] and Yiddish) to what is now Ukraine, the births of the 9 children of my Great Grandfather and Great Grandmother were recorded in the Lutheran Church Book in Volhynia. Had this not been done, we (my cousin Dan and I) would still be looking for the original 5 children mentioned in Great Aunt Adina's letter from 1990.
In looking at the GEDBAS database it also seems that Quackenburg was the Las Vegas of Poland. Seems most marriages took place there OR were just recorded there. At this point I don't even know if there was a ceremony or maybe they just jumped over a broom or something and were considered married until it was recorded in the church book.
Just this morning I found another European genealogy site. Maybe I'll find something there.
One of these days I'll find them.