Complex sentence: His death was officially reported as a suicide but Arbogast, his "magister militum" was suspected to have had a hand in it, an accusation found in the writings of Socrates of Constantinople, Orosius, and Zosimus.
Split into simpler sentences: His death was officially reported as a suicide but Arbogast, his magister militum was suspected to have had a hand in it. The accusation can be found in the writings of Socrates of Constantinople, Orosius, and Zosimus.