 The post-Julian Roman Empire was Christian, with one "officially sanctioned and legally enforced version" of (Nicene) Christianity.The Sassanid Empire in Persia was Zoroastrian, again with one officially sanctioned and legally enforced version of Zoroastrianism.On the Indian subcontinent, Vaisnava kingdoms (devotees of Vishnu and his incarnations) fought with Savia kingdoms (devotees of Shiva) for territorial control.