flourish, was not without both dignity and courtesy. The reference to the falling of the sky seems to give a glimpse of some primitive belief or myth of which it is no longer possible to discover the meaning.(10) The national oath by which the Celts bound themselves to the observance of their covenant with Alexander is remarkable. “If we observe not this engagement,” they said, “may the sky fall on us and crush us, may the earth gape and swallow us up, may the sea burst out and overwhelm us.” De Jubainville draws attention most appositely to a passage from the “Táin Bo Cuailgne,” in the Book of Leinster(11), where the Ulster heroes declare to their king, who wished to leave them in battle in order to meet an attack in another part of the field: “Heaven is above us, and earth beneath us, and the sea is round about us. Unless the sky shall fall with its showers of stars on the ground where we are camped, or unless the earth shall be rent by an earthquake, or unless the waves of the blue sea come over the forests of the living world, we shall not give ground.”(12) This survival of a peculiar oath-formula for more than a thousand years, and its reappearance, after being first heard of among the Celts of Mid-Europe, in a mythical romance of Ireland, is certainly most curious, and, with other facts which we shall note hereafter, speaks strongly for the community and persistence of Celtic culture.(13) *The Sack of Rome* We have mentioned two of the great wars of the Continental Celts; we come now to the third, that with the Etruscans, which ultimately brought them into conflict with the greatest power of pagan Europe, and led to their proudest feat of arms, the sack of Rome. About the year 400 B.C. the Celtic Empire seems to have reached the height of its power. Under a king named by Livy Ambicatus, who was probably the head of a dominant tribe in a military confederacy, like the German Emperor in the present day, the Celts seem to have been welded into a considerable degree of political unity, and to have followed a consistent policy. Attracted by the rich land of Northern Italy, they poured down through the passes of the Alps, and after hard fighting with the Etruscan inhabitants they maintained their ground there. At this time the Romans were pressing on the Etruscans from below, and Roman and Celt were acting in definite concert and alliance. But the Romans, despising perhaps the Northern barbarian warriors, had the rashness to play them false at the siege of Clusium, 391 B.C., a place which the Romans regarded as one of the bulwarks of Latium against the North. The Celts recognised Romans who had come to them in the sacred character of ambassadors fighting in the ranks of the enemy. The events which followed are, as they have come down to us, much mingled with legend, but there are certain touches of dramatic vividness in which the true character of the Celts appears distinctly recognisable. They applied,