Ammianus Marcellinus Res Gestae 15.5.4

[4] So when the abovementioned commander was traversing Gaul in the service of the government and driving forth the savages, who had now lost their confidence and courage, this same Dynamius, being restless in action, like the crafty man he was and practised in deceit, devised a wicked plot. He had as abettors and fellow conspirators, as uncertain rumours declared, Lampadius, ¹ the praetorian prefect, and Eusebius, former keeper of the privy purse, ² who had been nicknamed Mattyocopus, ³ and Aedesius, late master of the rolls, ⁴ all of whom the said prefect had arranged to have called to the consulship as his nearest friends. With a sponge he effaced the lines of writing, leaving only the signature intact, and wrote above it another text far different from the original, indicating that Silvanus in obscure terms was asking and urging his assistants within the palace or without official position, including both Tuscus Albinus and many more, to help him, aiming as he was at a loftier position and soon to mount to the imperial throne.