with many followers, to found new colonies in Italy and the Hercynian
forest.[46] Mythical as this may be, it suggests the hegemony of one
tribe or one chief over other tribes and chiefs, for Livy says that the
sovereign power rested with the Bituriges who appointed the king of
Celticum, viz. Ambicatus. Some such unity is necessary to explain Celtic
power in the ancient world, and it was made possible by unity of race or
at least of the congeries of Celticised peoples, by religious
solidarity, and probably by regular gatherings of all the kings or
chiefs. If the Druids were a Celtic priesthood at this time, or already
formed a corporation as they did later in Gaul, they must have
endeavoured to form and preserve such a unity. And if it was never so
compact as Livy's words suggest, it must have been regarded as an ideal
by the Celts or by their poets, Ambicatus serving as a central figure
round which the ideas of empire crystallised. The hegemony existed in
Gaul, where the Arverni and their king claimed power over the other
tribes, and where the Romans tried to weaken the Celtic unity by
opposing to them the Aedni.[47] In Belgium the hegemony was in the hands
of the Suessiones, to whose king Belgic tribes in Britain submitted.[48]
In Ireland the "high king" was supreme over other smaller kings, and in
Galatia the unity of the tribes was preserved by a council with regular
assemblies.[49]

The diffusion of the Ambicatus legend would help to preserve unity by
recalling the mythic greatness of the past. The Boii and Insubri
appealed to transalpine Gauls for aid by reminding them of the deeds of
their ancestors.[50] Nor would the Druids omit to infuse into their
pupils' minds the sentiment of national greatness. For this and for
other reasons, the Romans, to whom "the sovereignty of all Gaul" was an
obnoxious watch-word, endeavoured to suppress them.[51] But the Celts
were too widely scattered ever to form a compact empire.[52] The Roman