The more sagacious Italians admonished their eastern brethren of the folly and danger of such a hope; and convinced them, that the Medes and Persians were incapable of resisting the arms of the Huns; and that the easy and important acquisition would exalt the pride, as well as power, of the conqueror.  Instead of contenting himself with a moderate contribution and a military title, which equalled him only to the generals of Theodosius, Attila would proceed to impose a disgraceful and intolerable yoke on the necks of the prostrate and captive Romans, who would then be encompassed, on all sides, by the empire of the Huns.

While the powers of Europe and Asia were solicitous to avert the impending danger, the alliance of Attila maintained the Vandals in the possession of Africa.  An enterprise had been concerted between the courts of Ravenna and Constantinople for the recovery of that valuable province; and the ports of Sicily were already filled with the military and naval forces of Theodosius.  But the subtle Genseric, who spread his negotiations round the world, prevented their designs, by exciting the King of the Huns to invade the Eastern Empire; and a trifling incident soon became the motive, or pretence, of a destructive war.  Under the faith of the treaty of Margus, a free market was held on the northern side of the Danube, which was protected by a Roman fortress surnamed Constantia.  A troop of Barbarians violated the commercial security, killed or dispersed the unsuspecting traders, and levelled the fortress with the ground.  The Huns justified this outrage as an act of reprisal, alleged that the Bishop of Margus had entered their territories to discover and steal a secret treasure of their kings, and sternly demanded the guilty prelate, the sacrilegious spoil, and the fugitive subjects who had escaped from the justice of Attila.

The refusal of the Byzantine court was the signal of war; and the Maesians at first applauded the generous firmness of their sovereign.  But they were soon intimidated by the destruction of Viminiacum and the adjacent towns; and the people were persuaded to adopt the convenient maxim that a private citizen, however innocent or respectable, may be justly sacrificed to the safety of his country.  The Bishop of Margus, who did not possess the spirit of a martyr, resolved to prevent the designs which he suspected.  He boldly treated with the princes of the Huns; secured, by solemn oaths, his pardon and reward; posted a numerous detachment of Barbarians, in silent ambush, on the banks of the Danube; and, at the appointed hour, opened, with his own hand, the gates of his episcopal city.  This advantage, which had been obtained by treachery, served as a prelude to more honorable and decisive victories.