Relationships between kings and monasteries or convents were governed by three privileges: free election, immunity, and royal protection. While the first two privileges have been extensively investigated, royal protection has attracted little attention among medievalists, with the exception of German scholarship. The latter has usually emphasised a specific consequence of the use of this privilege, namely the transfer of ownership rights over the monastery or the convent from the founders’ family to the king. However, this was just one possible effect of royal protection, not necessarily the most common or most important. The distinguishing features of this privilege have been largely ignored, namely its nature as a right in personam , and not in rem , as well as its jurisdictional content, since royal protection allowed protected persons to be judged by the royal court. This article aims to explore the full political potential of royal protection, and to reconstruct the institutional dynamics that the use of this privilege could trigger in the Ottonian period. Two case studies are analysed comparatively: Central Italy and Eastern Saxony. Though different and distant from each other, these two political spaces can be fruitfully compared, as the Ottonians and the religious communities of these areas deliberately decided to make intensive use of royal protection to shape their mutual relationships. This comparative study reveals significant differences in the political application of the privilege in the two regions, in part reflecting a dissimilar understanding of the idea of royal protection itself. This privilege established a bilateral and asymmetrical relationship of variable intensity, which could change in time and space depending on the variable degree of political autonomy enjoyed by the protected abbot (abbess) and his (her) community as well as the different attitude of the king, acting as a lenient judge or as lord of those under his protection.