The assassination of Alexander Severus (222–235), the last of the Severans, brought to an end the Augustan Principate, and the empire descended into its third crisis, this time lasting nearly fifty years. Twenty five emperors obtained power in the space of forty-nine years, with at least fifty one claiming it. Most were either murdered or died in military campaigns against Rome's enemies that were now pressing hard on her frontiers. In addition to instability in governance and civil war the crisis years were marked by hyperinflation, plague and the first schism within the empire. The profound changes between the preceding Principate and succeeding Dominate, coincide with a shift from Classical Antiquity to Late Antiquity. It was also an era in which might of the far flung Roman Empire was now beginning to experience increasing pressure on its eastern and northern borders, whereas previously the balance of military power had concentrated on defending the eastern border.