De Synodis
Hilary's treatise on the various creeds and synods of the Arian controversy, including the Council of Sirmium.
Chapter I (The Six Days of Creation)
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Verse 26: Let Us Make Man in Our Image and Likeness
— Cited as source for the Council of Sirmium's anathema on those who explain "Let Us make man" otherwise than as addressed to the Trinity
"the Council of Sirmium, cited by Hilary in his book On the Synods, pronounces anathema on those who explain this passage otherwise."