From the late twelfth century onwards, we observe a gradual shift from a horizontal to a vertical relationship between king and commoners in the kingdoms of Denmark, Norway, and Sweden. This gradual transformation contributed to, and partly enabled, the growth of royal power in medieval Scandinavia. As elsewhere in Europe, kingship underwent a fundamental ideological change bringing about new forms of legitimisation of royal power according to which the king functioned as a rex iustus by divine grace. This elevated position placed the king above other members of the secular elite as he was glorified as God’s elected representative on earth. This chapter explores this process by analysing the preserved law material, and placing special emphasis on mutual obligations between king and commoners, considering the extent to which the king was bound by law, individual rights to pursue feuds, royal privileges, and crimes against the Crown. It shows, among other things, how the king was bound by the law in all the three Scandinavian countries up to the thirteenth century when differences started to appear. The kings in Denmark and Sweden were increasingly restricted by specific constitutional provisions, while the kings in Norway became less and less confined by law.