- City and seaport, which began as a Greek colony (Barion), on the Adriatic Sea in southeastern Italy;
- A late medieval Duchy;
- A province in modern Italy.
Bari belonged to the Lombard Principality of Benevento, c.668-847, when it was seized by the Arabs. The Emperor Louis II drove them out in 871, but he was forced from southern Italy by the Lombards and died in 875. By 888 the city was firmly in the hands of the Byzantine Empire and it became the capital of the Byzantine theme of Longobardia. With its capture by the Normans of Apulia in 1071, Byzantine rule in Italy ended. Bari belonged thereafter to the Kingdom in southern Italy.
In the 14th century Gianantonio del Balzo Orsini, Prince of Taranto, one of the most powerful men in the Kingdom of Naples, also held the Duchy of Bari, and after his death in 1463 it was held by various members of the Sforza family. The last of them, Bona, widow of King Sigismund I of Poland, alleged poisoner of her daughter-in-law and herself allegedly poisoned in 1558 by her lover, left the Duchy to King Philip II, of Naples and of Spain. In the Neapolitan Kingdom it formed the province of Terra di Bari.
The modern province extends along the coastal plain, while inland are the hills of Le Murge. It now belongs to the Puglia Region.