One of the church "dates" which you can see in the marriage books quite often is the Septuagesima Sunday (neděle devítník in Czech). It's often mentioned as one of the days when marriage bans took place. Marriage bans took place on three feast days prior to the marriage - and the feast day was usually a Sunday.
Septuagesima means seventieth and it was the 9th Sunday before Easter. It was the beginning of the preparation for the Lent period - last three weeks to enjoy festivities, to celebrate, for weddings to be held. That's why Septuagesima is so often mentioned as a term for the marriage bans - it was the last change to have a wedding before the Lent and Easter period when weddings were forbidden as it was not allowed to celebrate anything.
There was number of customs connected to the Septuagesima Sunday. There were special prayers said and special masses held in the churches in order to remind people the Lent and Easter is coming. Saturday prior to Septuagesima was also originally the day when the Nativity scene (so called betlém) was shown in the churches and homes - it was usually displayed for such a long time (today we usually have it till the Three Wise Men day and not longer).
Today Septuagesima is not considered a special Sunday anymore in the Roman Catholic church. It lost its importance after the Second Vatican Council as the pre-Lent period is not anymore important for the church.
If you want to know more, there is quite comprehensive article about Septuagesima on Wikipedia.