Caecilius Metellus overran the country and received a triumph and the surname _Dalmaticus_. But in 51 a Dalmatian raid on Liburnia led to a renewal of hostilities; the Roman armies were often worsted, and although in 39 Asinius Pollio gained some successes (see Horace, _Odes_ ii. 1. 15) these appear to have been exaggerated, and it was not until Octavian took the field in person that the Dalmatians submitted in 33. (For an account of the war see Appian, _Illyrica_, 24-28; Dio Cassius xlix. 38; Livy, _Epit._ 131, 132). They again revolted in 16 and 11, and in A.D. 6-9 joined the rebel Pannonians. Suetonius (_Tiberius_, 16) declares that they were the most formidable enemies with whom the Romans had had to contend since the Punic Wars. In A.D. 9, however, Tiberius entirely subjugated them, for which he was awarded a triumph in 12 (Dio Cass. lv. 23-29, lvi. 11-17; Vell. Pat. ii. 110-115). Thenceforward Dalmatia, Iapydia and Liburnia were united as the province of Illyricum. Latin civilization spread rapidly, the cultivation of the vine was introduced, gold-mining was carried on in Bosnia, and flourishing commercial cities arose along the coast. Illyria became one of the best recruiting grounds for the Roman legions; and in troubled times many Illyrian soldiers fought their way up from the ranks to the imperial purple. Claudius, Aurelian, Probus, Diocletian and Maximian were all sons of Illyrian peasants. It is probable, however, that most of the highland tribes now represented by the Albanians remained almost unaffected by Roman influence. The importance of Illyricum caused its name to be extended to many neighbouring districts; in the 2nd century A.D. the _Illyricus Limes_ included Noricum, Pannonia, Moesia, Dacia and Thrace. In the reorganization of the empire by Diocletian (285) the diocese of Illyricum was created; it comprised Pannonia, Noricum and Dalmatia, while Dacia and Macedonia, together called Eastern Illyricum, were added later. Either Diocletian or after him Constantine made Illyricum one of the four prefectures, each governed by a _praefectus praetorio_, into which the empire was divided. This prefecture included Pannonia, Noricum, Crete and the entire Balkan peninsula except Thrace, which was attached by Constantine to the prefecture of the East. From the partition of the empire in 285 until 379 Illyricum was included in the Western Empire, but thenceforward Eastern Illyricum was annexed to the Eastern Empire; its frontier was almost identical with the line of demarcation between Latin-speaking and Greek-speaking peoples, and roughly corresponded to the boundary which now severs Latin from Greek Christianity in the Balkan peninsula. The whole peninsula except Thrace was still known as Illyricum, but was subdivided into Illyris Barbara or Romana and Illyris Graeca (Eastern Illyricum with Greece and Crete). The Via Egnatia, the great line of road which connected Rome with