The Principate was the early period of the Roman Empire, beginning with the reign of Augustus as the first Roman emperor in 27 BC and conventionally lasting until the late third century, often linked to the Crisis of the Third Century. The Principate as a term is inspired by the position of princeps senatus that had existed during the previous Roman Republic. Augustus refashioned the concept of a princeps that had previously applied to Roman nobility, but now became a title for the sole ruler of Rome. Later Roman emperors also contributed in defining the role of the princeps in Roman society.