In the area of medieval Bosnia customs represented one of the most important income types which the medieval monarch could generate. However, that income started to be generated when charging customs duties was introduced in the 14th century or from the moment when the institutional change happened. Namely, in the preserved charters of Ban Matej Ninoslav any charges given by people of Dubrovnik to the Ban were not mentioned, therefore it is very likely that people from Dubrovnik ensured the privilege of not paying tithes through different gifts, what was ordinary in the world of that time when somebody wanted to gain favor of a certain ruler. Such custom (lat. consuetudo) lasted till the Ban Stephen II came to power when charging custom duties was established in Bosnian Banovina. It was also continued in the time of Ban Tvrtko. Introducing customs duties, understood as “efficient institutions”, was more suitable for Bosnian ruler than the existence of “inefficient alternatives”. In the procedure of forming customs duties Bosnian ruler had a power of their creating and abolishing, however, he was not alone in that procedure. During the time Bosnian-Hum noblemen started to use the same procedure and realistically they had such power to introduce or abolish charging customs duties in their estates.