<P> Christianity and traditional Roman religion proved incompatible . From the 2nd century onward, the Church Fathers had condemned the diverse non-Christian religions practiced throughout the Empire as "pagan". Constantine's actions have been regarded by some scholars as causing the rapid growth of Christianity, though revisionist scholars disagree . Constantine's unique form of Imperial orthodoxy did not outlast him . After his death in 337, two of his sons, Constantius II and Constans, took over the leadership of the empire and re-divided their Imperial inheritance . Constantius was an Arian and his brothers were Nicene Christians . </P> <P> Constantine's nephew Julian rejected the "Galilean madness" of his upbringing for an idiosyncratic synthesis of neo-Platonism, Stoic asceticism and universal solar cult . Julian became Augustus in 361 and actively but vainly fostered a religious and cultural pluralism, attempting a restitution of non-Christian practices and rights . He proposed the rebuilding of Jerusalem's temple as an Imperial project and argued against the "irrational impieties" of Christian doctrine . His attempt to restore an Augustan form of principate, with himself as primus inter pares ended with his death in 363 in Persia, after which his reforms were reversed or abandoned . The empire once again fell under Christian control, this time permanently . </P> <P> In 380, under Theodosius I, Nicene Christianity became the official state religion of the Roman Empire . Christian heretics as well as non-Christians were subject to exclusion from public life or persecution, though Rome's original religious hierarchy and many aspects of its ritual influenced Christian forms, and many pre-Christian beliefs and practices survived in Christian festivals and local traditions . </P> <P> The Western emperor Gratian refused the office of pontifex maximus, and against the protests of the senate, removed the altar of Victory from the senate house and began the disestablishment of the Vestals . Theodosius I briefly re-united the Empire: in 391 he officially adopted Nicene Christianity as the Imperial religion and ended official support for all other creeds and cults . He not only refused to restore Victory to the senate - house, but extinguished the Sacred fire of the Vestals and vacated their temple: the senatorial protest was expressed in a letter by Quintus Aurelius Symmachus to the Western and Eastern emperors . Ambrose, the influential Bishop of Milan and future saint, wrote urging the rejection of Symmachus's request for tolerance . Yet Theodosius accepted comparison with Hercules and Jupiter as a living divinity in the panegyric of Pacatus, and despite his active dismantling of Rome's traditional cults and priesthoods could commend his heirs to its overwhelmingly Hellenic senate in traditional Hellenic terms . He was the last emperor of both East and West . </P>

When did rome begin following a monotheistic religion