in antiquity, a region of northern Africa occupying what is now the eastern part of modern Algeria. At the end of the first millennium B.C., the nomadic Numidian Massyli and Masaeslyi tribes made a gradual transition to land cultivation and settled stock raising. This transition was accompanied by the rise of cities, such as Cirta (the main city), Thugga, Theveste, and Sicca Veneria, and the development of the cities into poleis.
Numidia was conquered by Carthage in the third century B.C. The Numidians repeatedly rose up against Carthaginian domination. During the Second Punic War (218–201 B.C.), Masinissa, king of the eastern portion of Numidia, aided the Romans; in return for his aid, the Romans helped him to become ruler of all Numidia in 201 B.C. Under Masinissa (ruled 201–149 B.C.), the Numidian kingdom was greatly strengthened: its size increased, cities grew, and commercial ties were increased with the entire Mediterranean region.
Between 111 and 105 B.C., the Numidian king Jugurtha waged a war with Rome. He suffered defeat, was taken prisoner, and was executed. In 46 B.C., Numidia became the Roman province of Africa Nova. It was conquered by the Vandals in 429–30 A.D. and by the Byzantines in 533. The region was seized by the Arabs in the seventh century.