Duklja (, , ) was a medieval
Serb state which roughly encompassed the territories of present-day southeastern
Montenegro, from the
Bay of Kotor in the west to the
Bojana river in the east, and to the sources of the Zeta and Moraca rivers in the north. First mentioned in 10th– and 11th century Byzantine chronicles, it was a
vassal of the
Byzantine Empire until it became independent in 1040 under
Stefan Vojislav ( 1034–43) who rose up and managed to take over territories of the earlier
Serbian Principality, founding the
Vojislavljevic dynasty. Between 1043 and 1080, under
Mihailo Vojislavljevic ( 1050–81), and his son,
Constantine Bodin (r. 1081–1101), Duklja saw its apogee. Mihailo was given the nominal title
King of Slavs by the Pope after having left the Byzantine camp and supported a Slavic uprising in the Balkans, in which his son Bodin played a central part. Having incorporated the Serbian hinterland (the core of the earlier Serbian Principality, known as
Raška) and installed vassal rulers there, this maritime principality emerged as the most powerful Serb polity, seen in the titles used by its rulers ("Prince of Serbia", "of Serbs"). However, its rise was short-lived, as Bodin was defeated by the Byzantines and imprisoned; pushed to the background, his relative and vassal Vukan became independent in Raška, which continued the fight against the Byzantines while Duklja was struck with civil wars. Between 1113 and 1149 Duklja was the centre of Serbian–Byzantine conflict, with members of the Vojislavljevic as protégés of either fighting each other for power. Duklja was then incorporated as a
crown land of the
Grand Principality of Serbia ruled by the
Vukanovic dynasty, subsequently known as
Zeta, remaining so until the fall of the
Serbian Empire in the 14th century.