Apparently Czechs practiced ultimogeniture, which is “the tradition of inheritance by the last-born of the entirety of, or a privileged position in, a parent’s wealth, estate or office” according to Wikipedia.
So, before the laws passed allowing land to be subdivided (circa ~1850), the youngest son would inherit the father’s house.
I wonder if this pertains to all marriages; would it be the youngest son of all of the father’s marriages, or just his first wife’s? How were these things determined?