Illyricum is the name of the Roman province located on the eastern coast of the Adriatic Sea and north of Macedonia.

Rome began its conquest of Illyricum as a result of the shipping hazard her state-sanctioned pirates posed. In the late third century B.C. Rome went to war against the Illyrians twice, but it took two centuries before the Illyrians came under Roman dominance. Slavic invasion of the sixth century A.D. and later changed the ethnic composition of the Illyrians.