Morava and Timok (eastern Serbia) were subjected by the Bulgars. With the
arrival of the Magyars, in the ninth century, a wall was raised between
the Serbs and central and western Europe on land. Croatia and Slavonia
(between the Save and the Drave) were gradually drawn into the orbit of
the Hungarian state, and in 1102, on the death of its own ruler, Croatia
was absorbed by Hungary and has formed part of that country ever since.
Hungary, aiming at an outlet on the Adriatic, at the same time subjected
most of Dalmatia and parts of Bosnia. In the west Venice had been steadily
growing in power throughout the tenth century, and by the end of it had
secured control of all the islands off Dalmatia and of a considerable part
of the coast. All the cities on the mainland acknowledged the supremacy of
Venice and she was mistress of the Adriatic.

In the interior of the Serb territory, during the eleventh and twelfth
centuries, three political centres came into prominence and shaped
themselves into larger territorial units. These were: (1) Raska, which had
been Caslav's centre and is considered the birth-place of the Serbian
state (this district, with the town of Ras as its centre, included the
south-western part of the modern kingdom of Serbia and what was the
Turkish _sandjak_ or province of Novi-Pazar); (2) Zeta, on the coast (the
modern Montenegro); and (3) Bosnia, so called after the river Bosna, which
runs through it. Bosnia, which roughly corresponded to the modern province
of that name, became independent in the second half of the tenth century,
and was never after that incorporated in the Serbian state. At times it
fell under Hungarian influence; in the twelfth century, during the reign
of Manuel Comnenus, who was victorious over the Magyars, Bosnia, like all
other Serb territories, had to acknowledge the supremacy of
Constantinople.

It has already been indicated that the Serbs and Croats occupied territory