When the Greeks shivered in the cold north-wind, they thought that Boreas, one of their divinities who dwelt beyond the high mountains, had loosened the blast from a mysterious cave. The North was to them an unknown region. Far beyond the hills they thought there dwelt a nation known as Hyperboreans, or people beyond the region of Boreas, who lived in an atmosphere of feathers, enjoying Arcadian happiness, and stretching their peaceful lives out to a thousand years. That which is unknown is frightful to the ignorant or the superstitious, and so it was that the North was a land in which all that was alarming might be conjured up. The inhabitants of the Northern lands were called Gauls by the Romans. They lived in villages with no walls about them, and had no household furniture; they slept in straw, or leaves, or grass, and their business in life was either agriculture or war. They were hardy, tall, and rough in appearance; their hair was shaggy and light in color compared with that of the Italians, and their fierce appearance struck the dwellers under sunnier climes with dread.

These warlike people had come from the plains of Asia, and in Central and Northern Europe had increased to such an extent that they could at length find scarcely enough pasturage for their flocks. The mountains were full of them, and it was not strange that some looked down from their summits into the rich plains of Italy, and then went thither; and, tempted by the crops, so much more abundant than they had ever known, and by the wine, which gave them a new sensation, at last made their homes there. It was a part of their life to be on the move, and by degrees they slipped farther and farther into the pleasant land. They flocked from the Hercynian forests, away off in Bohemia or Hungary, and swarmed over the Alps; they followed the river Po in its course, and they came into the region of the Apennines too. [Footnote: No one knows exactly when the Gauls first entered Northern Italy. Some think that it was as long back as the time of the Tarquins, while others put it only ten or twenty years before the battle of the Allia - 410-400 B.C.] It was they who had weakened the Etruscans and made it possible for the Romans to capture Veii. Afterwards they came before the city of Clusium (B.C. 391), and the people in distress begged for aid from Rome. No help was given, but ambassadors were sent to warn the invaders courteously not to attack the friends of the Roman people who had done them no harm. Such a request might have had an effect upon a nation that knew the Romans better, but the fierce Northerners who knew nothing of courtesy replied that if the Clusians would peaceably give up a portion of their lands, no harm should befall them; but that otherwise they should be attacked, and that in the presence of the Romans, who might thus take home an account of how the Gauls excelled all other mortals in bravery. Upon being asked by what right they proposed to take a part of the Clusian territory, Brennus, the leader of the barbarians, replied that all things belonged to the brave, and that their right lay in their trusty swords.

In the battle that ensued, the Roman ambassadors fought with the Clusians, and one of them killed a Gaul of great size and stature. This was made the basis for an onset upon Rome itself. Then the Romans must have remembered how just before the hero of Veii had gone into banishment, a good and respectable man reported to the military tribunes that one night as he was going along the street near the temple of Vesta, he heard a voice saying plainly to him: "Marcus Cædicius, the Gauls are coming!" Probably they remembered, too, how lightly they esteemed the information, and how even the tribunes made sport of it. Now the Northern scourge was actually rushing down upon them, and Camillus was gone! In great rage the invaders pushed on towards the city, alarming all who came in their way by their numbers, their fierceness, and the violence with which they swept away all opposition. There was little need of fear, however, for the rough men took nothing from the fields, and, as they passed the cities, cried out that they were on their way to Rome, and that they considered the inhabitants of all cities but Rome friends who should receive no harm.

The Romans had a proverb to the effect that whom the gods wish to destroy they first make mad, and, according to their historian Livy, it was true in this case, for when the city was thus menaced by a new enemy, rushing in the intoxication of victory and impelled by the fury of wrath and the thirst for vengeance, they did not take any but the most ordinary precautions to protect themselves; leaving to the usual officers the direction of affairs, and not bestirring themselves as much as they did when threatened by the comparatively inferior forces of the neighboring states. They even neglected the prescribed religious customs and the simplest precautions of war. When they sent out their army they did not select a fit place for a camp, nor build ramparts behind which they might retreat, and they drew up the soldiers in such a way that the line was unusually weak in the parts it presented to the on-rushing enemy.