[3][4] Procopius (De bello Gothico, I.18.39–41), calls him one of the archontes (leaders) of the Goths and "a man of no mean station".
[5][3] He gave a speech at the Porta Salaria[2] in which he reminded the Romans that the Ostrogoths were capable of defending them, but the Greeks (i.e., Byzantines) had only ever came to Italy before as "actors of tragedy and mimes and thieving sailors".
[c] Procopius (II.13.5–15) describes him as an archon dispatched by Witigis against the Byzantine forces under Conon at Ancona in the summer of 538, for which task Vacimus took men from the garrison of Osimo.
[9] Possibly Wacces is the unnamed individual mentioned in an earlier letter of Cassiodorus who was put in charge of victualing the army in Rome in such a way as to spread the burden of its upkeep fairly across the populace.
If his identification with Vacis is correct, then he must have been part of the faction of the aristocracy that immediately threw its support behind Witigis despite the latter's poor treatment of the deposed Theodahad.