The male members of all branches of the Kolowrat family concluded a Family Agreement. On January 29, 1629, this Agreement was made valid by Emperor Ferdinand II. The Agreement stipulated that the male descendants must take their wives exclusively from among the aristocracy. If they failed to do so, their descendants would not be recognized as rightful members of the family, and would even be prohibited from using the family coat of arms and the family name. They would also forfeit the right to the family legacy or to receive inheritance.
The only family member who eventually encountered a problem with being recognized as a full-fledged member of the family was Jan Václav Count Kolowrat-Nowohradský (1638–1690), who was born into the unequal marriage between his father, Count Zdeněk and Eleonora de Rojas. Emperor Ferdinand III., however, ruled in favor of Count Jan Václav in a subsequent lawsuit, thus recognizing him as his father’s rightful heir. Until then, all members of the family had strictly followed the rules of the Agreement. The ancestral Agreement became void with the establishment of the Civil Code in 1811.
An unequal marriage was also made by Leopold Maria Count Kolowrat-Krakowský (1804–1863), who in 1850 married Natalia Blaszezynska. The count’s relatives sent a complaint to the provincial court, which rejected it however. At that time, the Civil Code was already in force, which from a legal standpoint took precedence over a family agreement.
Among other things, the Family Agreement also stipulated the upkeep of the monastery in Dolní Ročov, preservation of the family coat-of-arms and maintaining a family archive. Every family branch collected the most valuable documents, had copies made and organized in five books, which were always maintained by the oldest member of the given branch of the family.