Procopius, History of the Wars — Book VI: The Gothic War…
“ Belisarius then commanded his guards to enter, whereupon Constantinus said: "In order, plainly, to have them kill me." "By no means," said Belisarius, "but to have them compel your bodyguard Maxentiolus, who forcibly carried away the daggers for you, to restore to the man what he took from him by violence." But Constantinus, thinking that he was to die that very instant, wished to do some great deed before he should suffer anything himself. He accordingly drew the dagger which hung by his thigh and suddenly thrust it at the belly of Belisarius. ”
