Complex sentence: The theory of a Constantinian shift also denies the history that followed Constantine's legalization of Christianity as well as specifics that proceeded it, a history that contained a brief unity between the Arians and Trinitarians.
Split into simpler sentences: The theory of a Constantinian shift also denies the history that followed Constantine's legalization of Christianity as well as specifics that proceeded it. A history that contained a brief unity between the Arians and Trinitarians.