The Secret History by Procopius

The father of Belisarius's wife, a lady whom I have mentioned in my former books, was (and so was her grandfather) a charioteer, exhibiting that trade in Constantinople and Thessalonica. Her mother was one of the wenches of the theater; and she herself from the first led an utterly wanton life. Acquainted with magic drugs used by her parents before her, she learned how to use those of compelling qualities and became the wedded wife of Belisarius, after having already borne many children.

Now she was unfaithful as a wife from the start, but was careful to conceal her indiscretions by the usual precautions; not from any awe of her spouse (for she never felt any shame at anything, and fooled him easily with her deceptions), but because she feared the punishment of the Empress. For Theodora hated her, and had already shown her teeth. But when that Queen became involved in difficulties, she won her friendship by helping her, first to destroy Silverius, as shall be related presently,2 and later to ruin John of Cappadocia,3 as I have told elsewhere. After that, she became more and more fearless, and casting all concealment aside, abandoned herself to the winds of desire.