Control of the southern duchies allowed Conrad to continue the process begun under the Ottonian dynasty, centralizing the Emperors authority over the Empire at the expense of the regional dukes. Conrad broke with Ottonian tradition, however, in favoring a more strict means of controlling rebellious vassals. Whereas the Ottonians followed a policy of informal public submission and subsequent reconciliation, Conrad used treason trials to declare rebels as "public enemies" to legitimize his subsequent harsh treatment, as he had done with Ernest II of Swabia and Adalbero. The nobles saw use of these treason trials not as mere power shifts in favor of the Emperor, but as a cruel breach of German tradition.