 Under Augustus, whose most important political priority was to place the military under a permanent and unitary command, the Emperor was the legal commander of each legion but exercised that command through a "legatus" (legate) he appointed from the Senatorial elite.In a province with a single legion, the legate would command the legion ("legatus legionis") and also serve as provincial governor, while in a province with more than one legion, each legion would be commanded by a legate and the legates would be commanded by the provincial governor (also a legate but of higher rank).During the later stages of the Imperial period (beginning perhaps with Diocletian), the Augustan model was abandoned.