Placentia, and was
advancing toward Ariminum on the Adriatic, and driving before him the
Roman army under Porcius. Nor when the consul Livius had come up, and
united the second and third armies of the North, could he make head
against the invaders. The Romans still fell back before Hasdrubal beyond
Ariminum, beyond the Metaurus, and as far as the little town of Sena, to
the southeast of that river. Hasdrubal was not unmindful of the
necessity of acting in concert with his brother. He sent messengers to
Hannibal to announce his own line of march, and to propose that they
should unite their armies in South Umbria and then wheel round against
Rome. Those messengers traversed the greater part of Italy in safety,
but, when close to the object of their mission, were captured by a Roman
detachment; and Hasdrubal's letter, detailing his whole plan of the
campaign, was laid, not in his brother's hands, but in those of the
commander of the Roman armies of the South. Nero saw at once the full
importance of the crisis. The two sons of Hamilcar were now within two
hundred miles of each other, and if Rome were to be saved the brothers
must never meet alive. Nero instantly ordered seven thousand picked men,
a thousand being cavalry, to hold themselves in readiness for a secret
expedition against one of Hannibal's garrisons, and as soon as night had
set in he hurried forward on his bold enterprise; but he quickly left
the southern road toward Lucania, and, wheeling round, pressed northward
with the utmost rapidity toward Picenum. He had, during the preceding
afternoon, sent messengers to Rome, who were to lay Hasdrubal's letters
before the senate. There was a law forbidding a consul to make war or
march his army beyond the limits of the province assigned to him; but in
such an emergency, Nero did not wait for the permission of the senate to
execute his project, but informed them that he was already on his march
to join Livius against Hasdrubal. He advised them to send the two
legions which formed the home garrison on to Narnia, so as to defend
that pass of the Flaminian road against Hasdrubal, in case he should
march upon Rome before the consular armies could attack him. They were
to supply the place of these two legions at Rome by a levy _en masse_ in
the city, and by ordering up the reserve legion from Capua. These were
his communications to the senate. He also sent horsemen forward along
his line of march, with orders to the local aut