concealment was interpreted as an evidence of guilt, and the measures which Aper had taken to secure his election became the immediate occasion of his ruin Yet, even in the transport of their rage and grief, the troops observed a regular proceeding, which proves how firmly discipline had been reestablished by the martial successors of Gallienus. A general assembly of the army was appointed to be held at Chalcedon, whither Aper was transported in chains, as a prisoner and a criminal. A vacant tribunal was erected in the midst of the camp, and the generals and tribunes formed a great military council. They soon announced to the multitude that their choice had fallen on Diocletian, commander of the domestics or body-guards, as the person the most capable of revenging and succeeding their beloved emperor. The future fortunes of the candidate depended on the chance or conduct of the present hour. Conscious that the station which he had filled exposed him to some suspicions, Diocletian ascended the tribunal, and raising his eyes towards the Sun, made a solemn profession of his own innocence, in the presence of that all-seeing Deity. Then, assuming the tone of a sovereign and a judge, he commanded that Aper should be brought in chains to the foot of the tribunal. "This man," said he, "is the murderer of Numerian;" and without giving him time to enter on a dangerous justification, drew his sword, and buried it in the breast of the unfortunate præfect. A charge supported by such decisive proof was admitted without contradiction, and the legions, with repeated acclamations, acknowledged the justice and authority of the emperor Diocletian.

Before we enter upon the memorable reign of that prince, it will be proper to punish and dismiss the unworthy brother of Numerian. Carinus possessed arms and treasures sufficient to support his legal title to the empire. But his personal vices overbalanced every advantage of birth and situation. The most faithful servants of the father despised the incapacity, and dreaded the cruel arrogance, of the son. The hearts of the people were engaged in favor of his rival, and even the senate was inclined to prefer a usurper to a tyrant. The arts of Diocletian inflamed the general discontent; and the winter was employed in secret intrigues, and open preparations for a civil war. In the spring, the forces of the East and of the West encountered each other in the plains of Margus, a small city of Mæsia, in the neighborhood of the Danube. The troops, so lately returned from the Persian war, had acquired their glory at the expense of health and numbers; nor were they in a condition to contend with the unexhausted strength of the legions of Europe. Their ranks were broken, and, for a moment, Diocletian despaired of the purple and of life. But the advantage which Carinus had obtained by the valor of his soldiers, he quickly lost by the infidelity of his officers. A tribune, whose wife he had seduced, seized the opportunity of revenge, and, by a single blow, extinguished civil discord in the blood of the adulterer.