devoted to securing control
of the peninsula, but during the Third century B.C. Thrace was invaded
from the north and laid waste by the Celts, who had already visited
Illyria. The Celts vanished by the end of that century, leaving a few
place-names to mark their passage. The city of Belgrade was known until
the seventh century A.D. by its Celtic name of Singidunum. Naissus, the
modern Nish, is also possibly of Celtic origin. It was towards 230 B.C.
that Rome came into contact with Illyricum, owing to the piratical
proclivities of its inhabitants, but for a long time it only controlled
the Dalmatian coast, so called after the Delmati or Dalmati, an Illyrian
tribe. The reason for this was the formidable character of the mountains
of Illyria, which run in several parallel and almost unbroken lines the
whole length of the shore of the Adriatic and have always formed an
effective barrier to invasion from the west. The interior was only very
gradually subdued by the Romans after Macedonia had been occupied by them
in 146 B.C. Throughout the first century B.C. conflicts raged with varying
fortune between the invaders and all the native races living between the
Adriatic and the Danube. They were attacked both from Aquileia in the
north and from Macedonia in the south, but it was not till the early years
of our era that the Danube became the frontier of the Roman Empire.

In the year A.D. 6 Moesia, which included a large part of the modern
kingdom of Serbia and the northern half of that of Bulgaria between the
Danube and the Balkan range (the classical Haemus), became an imperial
province, and twenty years later Thrace, the country between the Balkan
range and the Aegean, was incorporated in the empire, and was made a
province by the Emperor Claudius in A.D. 46. The province of Illyricum or
Dalmatia stretched between the Save and the Adriatic, and Pannonia lay
between the Danube and the Save. In 107 A.D. the Emperor Trajan conquered
the Dacians beyond the lower Danube, and organized a province of Dacia out
of territory roughly equivalent to the modern Wallachia and Transylvania,
This trans-Danubian territory did not remain attached to the empire for
more than a hundred and fifty years; but within the river line a vast belt
of country, stretching from the head of the Adriatic to the mouths of the
Danube on the Black Sea, was Romanized through and through. The Emperor
Trajan has been called the Charlemagne of the Balkan peninsula;