Domitian had continued and developed the policy initiated by Vespasian regarding the position of the troops on the border, especially on the rivers - ripae -, in places where they could control the ways of access, but he also put the bases of a linear system of fortifications on a castling road, in the newly conquered territories behind the Rhine and Danube. What seems interesting is that Domitian had not been tempted to experience these new principles at the north of the Danube, preferring in turn the long used technique for ending the conflict with the Dacians and the Getae, through customary rapports, maintained by means of subsidiary in order to make them not only efficiently, but also to guarantee him the loyalty of the kings.
Due to these stabilizing troops methods in key-places along the border, one had conceived a method to establish the extent of the border provinces.
The research process, constantly advancing, permits new steps towards completely knowledge. Reanalyzing the already known data from ancient sources, from the light of the newly archaeological and epigraphic evidence, is not only necessary, but it affects our better understanding of them.
Due to such an analyze of the historic sources we are able to assert that the extend of Dacia province is the outcome of the Empire's account with Decebalus' kingdom and neighboring Geto-Dacians realms, which entered or not in alliance with the last Dacian king.