Emperor Diocletian (284) undertook the restoration of the State. He ended the Principate and introduced the Tetrarchy which sought to increase state power. The most marked feature was the unprecedented intervention of the State down to the city level: whereas the State had submitted a tax demand to a city and allowed it to allocate the charges, from his reign the State did this down to the village level. In a vain attempt to control inflation, he imposed price controls which did not last. He or Constantine regionalised the administration of the empire which fundamentally changed the way it was governed by creating regional dioceses (the consensus seems to have shifted from 297 to 313/14 as the date of creation due to the argument of Constantin Zuckerman in 2002 "Sur la liste de Verone et la province de grande armenie, Melanges Gilber Dagron). The existence of regional fiscal units from 286 served as the model for this unprecedented innovation. The emperor quickened the process of removing military command from governors. Henceforth, civilian administration and military command would be separate. He gave governors more fiscal duties and placed them in charge of the army logistical support system as an attempt to control it by removing the support system from its control. Diocletian ruled the eastern half, residing in Nicomedia. In 296, he elevated Maximian to ''Augustus'' of the western half, where he ruled mostly from Mediolanum when not on the move. In 292, he created two 'junior' emperors, the Caesars, one for each Augustus, Constantius for Britain, Gaul, and Spain whose seat of power was in Trier and Licinius in Sirmium in the Balkans. The appointment of a Caesar was not unknown: Diocletian tried to turn into a system of non-dynastic succession. Upon abdication in 305, the Caesars succeeded and they, in turn, appointed two colleagues for themselves.