PANNONIA, a Roman province, was bounded on the W. by Noricum and Italy, on the S. by Illyricum and Mesia, and on the E. and N. by the Danube, and corresponded to that tract including Croatia, Slavonia, and portions of Austria, Hungary, and Bosnia. The early history of the country is involved in obscurity. Some suppose that its original inhabitants were Pannonians, who gradually came to call themselves Pannonians. A more probable opinion is, that it was colonized by Celtic tribes. At any rate, in 35 B.C. the Romans found the district in a low state of civilization. The extensive forests which cumbered the soil prevented the pursuits of agriculture; and the natives, divided into several tribes, which seem to have acknowledged separate chiefs, were addicted to war and rapine. From that date, however, a change slowly began to come over the social state and government of Pannonia. In 8 A.D., after an obstinate resistance, it was ultimately subjugated and reduced to the form of a Roman province by Tiberius. In the second century it was divided into two parts, Upper Pannonia, on the W., and Lower Pannonia, on the E. In the third and fourth centuries the emperors Probus and Galerius cleared the soil of much of the wood, and made room for the operations of agriculture. Meanwhile roads had been made, colonies had been planted, and Roman legions in the various fortresses, and a Roman fleet on the Danube, protected the government of the country. Pannonia retained this social organization until the middle of the fifth century, when it was ceded to the Huns.
The most important towns in Lower Pannonia were—Vindobona (Vienna), Carnuntum, Sabaria (Sarwar), Emona (Laybach), and Siscia (Siszege). Those in Upper Pannonia were Acincum (Alt-Buda), Mursa (Erzsek), and
Sirmium. The principal rivers were the Arrabo (Raab), the Dravus (Drave), and the Savus (Sare), all flowing into the Danube.