But despite this gesture of universality, the Severan dynasty was tumultuous—an emperor's reign was ended routinely by his murder or execution—and following its collapse, the Roman Empire was engulfed by the Crisis of the Third Century, a period of invasions, civil strife, economic disorder, and plague.[9] In defining historical epochs, this crisis is typically viewed as marking the start of the Late Roman Empire,[10] and also the transition from Classical Antiquity to Late Antiquity. Diocletian (reigned 284–305) brought the Empire back from the brink, but declined the role of princeps and became the first emperor to be addressed regularly as domine, "master" or "lord".[11] This marked the end of the Principate, and the beginning of the Dominate. Diocletian's reign also brought the Empire's most concerted effort against the perceived threat of Christianity, the "Great Persecution".