e had grown
very powerful under the Biturigian king Ambigatus. They appear to have
spread southwards into Spain, occupying most of that country as far
south as Gades (Cadiz), some tribes, e.g. Turdentani and Turduli,
forming permanent settlements and being still powerful there in Roman
times; and in northern central Spain, from the mixture of Celts with the
native Iberians, the population henceforward was called Celtiberian.
About this time also took place a great invasion of Italy; Segovisus and
Bellovisus, the nephews of Ambigatus, led armies through Switzerland,
and over the Brenner, and by the Maritime Alps, respectively (Livy V.
34). The tribes who sent some of their numbers to invade Italy and
settle there were the Bituriges, Arverni, Senones, Aedui, Ambarri,
Carnuti and Aulerci.

Certain material remains found in north Italy, e.g. at Sesto Calende,
may belong to this invasion. The next great wave of Celts recorded was
that which swept down on north Italy shortly before 400 B.C. These
invaders broke up in a few years the Etruscan power, and even occupied
Rome herself after the disaster on the Allia (390 B.C.). Bought off by
gold they withdrew from Rome, but they continued to hold a great part of
northern Italy, extending as far south as Sena Gallica (_Sinigaglia_),
and henceforward they were a standing source of danger to Rome,
especially in the Samnite Wars, until at last they were either subdued
or expelled, e.g. the Boii from the plains of the Po. At the same time
as the invasion of Italy they had made fresh descents into the Danube
valley and the upper Balkan, and perhaps may have pushed into southern
Russia, but at this time they never made their way into Greece, though
the Athenian ladies copied the style of hair and dress of the Cimbrian
women. About 280 B.C. the Celts gathered a great host at the head of the
Adriatic, and accompanied by the Illyrian tribe of Autariatae, they
overthrew the Macedonians, overran Thessaly, and invaded Phocis in order
to sack Delphi, but they were finally repulsed, chiefly by the efforts
of the Aetolians (279 B.C.). The remnant of those who returned from
Greece joined that part of their army which had remained in Thrace, and
marched for the Hellespont. Here some of their number settled near
Byzantium, having conquered the native Thracians, and made Tyle their
capital. The Byzantines had to pay them a yearly tribute of 80 talents,
until on the death of the Gallic king Cavarus (s