The Roman History · Amm. 21.16.8

Having now briefly enumerated his good qualities with which we have been able to become acquainted, let us now proceed to speak of his vices. In other respects he was equal to average princes, but if he had the slightest reason (even if founded on wholly false information) for suspecting any one of aiming at supreme power, he would at once institute the most rigorous inquiry, trampling down right and wrong alike, and outdo the cruelty of Caligula, Domitian, or Commodus, whose barbarity he rivalled at the very beginning of his reign, when he shamefully put to death his own connections and relations.

Ammianus Marcellinus · translated by C. D. Yonge · 1911 reprint
C. D. Yonge translation (preface dated February 1862); G. Bell and Sons, 1911; Project Gutenberg #28587
Passage preview. Read in context for the complete text, notes and references.