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.

The Illyrian frontier was covered by a line of castles and fortresses;
and though the greatest part of them consisted only of a single tower,
with a small garrison, they were commonly sufficient to repel or to
intercept the inroads of an enemy who was ignorant of the art and
impatient of the delay of a regular siege. But these slight obstacles
were instantly swept away by the inundation of the Huns. They destroyed,
with fire and sword, the populous cities of Sirmium and Singidunum, of
Ratiaria and Marcianopolis, of Naissus and Sardica; where every
circumstance of the discipline of the people and the construction of the
buildings had been gradually adapted to the sole purpose of defence. The
whole breadth of Europe, as it extends above five hundred miles from the
Euxine to the Hadriatic, was at once invaded and occupied and desolated
by the myriads of Barbarians whom Attila led into the field. The public
danger and distress could not, however, provoke Theodosius to interrupt
his amusements and devotion or to appear in person at the head of the
Roman legions.

But the troops which had been sent against Genseric were hastily
recalled from Sicily; the garrisons on the side of Persia were
exhausted; and a military force was collected in Europe, formidable by
their arms and numbers, if the generals had understood the science of
command and their soldiers the duty of obedience. The armies of the
Eastern Empire were vanquished in three successive engagements; and the
progress of Attila may be traced by the fields of battle. The two