Complex sentence: A history that contained a brief unity between the Arius and Trinitarians when Julian the Apostate ascended after Constantine II, to the throne of the Eastern Roman Empire and began to reinstate paganism (see Neoplatonism and theurgy) at the expense of christianity.
Split into simpler sentences: A history that contained a brief unity between the Arius and Trinitarians. Julian then began to reinstate paganism (see Neoplatonism and theurgy) at the expense of christianity.