The ratio behind the prohibition for spouses to donate to each other. Monopolising matrimonial property law in the dotal system. The present inquiry is based on the premise that the riddle of the highly contested rationale of the prohibition of donations between spouses can only be solved by taking into account the legal basis of this prohibition. The classical jurists treated the prohibition within the ius dotium, shorthand for 'matrimonial property regime', a legal matter heavily transformed by the lex Iulia et Papia which followed the goal of inciting the upper class to get married which would guarantee the desired offspring and control over the Emperor's subjects. Considering the palingenetic context of the treatises on the prohibition, the lex Iulia et Papia is to be considered the legal basis of the prohibition which, therefore, has the purpose of channelling all economical transactions between the spouses into the ius dotium which in turn serves the goals of the lex Iulia et Papia. To sum it up: The prohibition was another legal ordinance in Augustus' arsenal serving his fight for moral renewal, that is to say limitation of civil liberties, and the consolidation of his power.