Lactantius

“ Maximin Daia was incensed at the nomination of Licinius to the dignity of emperor, and he would no longer be called Cæsar, or allow himself to be ranked as third in authority. Galerius, by repeated messages, besought Daia to yield, and to acquiesce in his arrangement, to give place to age, and to reverence the grey hairs of Licinius. But Daia became more and more insolent. He urged that, as it was he who first assumed the purple, so, by possession, he had right to priority in rank; and he set at nought the entreaties and the injunctions of Galerius. ”