Stefan Uroš V in the context of "Balsha"

Zeta (Serbian Cyrillic: Зета; Albanian: Zetës; Latin: Zenta or Genta) was one of the medieval polities that existed between 1371 and 1421, whose territory encompassed parts of present-day southern Montenegro and northern Albania, ruled by the House of Balšić.

Zeta was a crown land of the Grand Principality and Kingdom of Serbia, ruled by heirs to the Serbian throne from the Nemanjić dynasty. In the mid-14th century, Zeta was divided into Upper and Lower Zeta, governed by magnates. After Stefan Dušan (r. 1331–55), his son Stefan Uroš V ruled Serbia during the fall of the Serbian Empire, through a gradual disintegration of the Empire as a result of decentralization in which provincial lords gained semi-autonomy and eventually independence. The Balšići wrestled the Zeta region in 1356–1362 when they removed the two rulers in Upper and Lower Zeta. Ruling as lords, they empowered themselves and over the decades became an important player in Balkan politics. Zeta was united into the Serbian Despotate in 1421, after Balša III abdicated and passed the rule to his uncle, Despot Stefan Lazarević (maternally a Nemanjić).

The fall of the Serbian Empire was a decades-long process in the late 14th century. Following the death of the childless Emperor Stefan Uroš V in 1371, the Serbian Empire was left without an heir and the magnates, velikaši, obtained the rule of its provinces and districts (in so-called feudal fragmentation), continuing their offices as independent with titles such as gospodin, and despot, given to them during the Empire. This period is known as the dissolution or the beginning of the fall of the Serbian Empire.

Between 1365 and 1371, King Vukašin was the co-ruler of Emperor Uroš, ruling the southern half, thus the Empire may be viewed as a de facto diarchy. Before 1371, the nobility were either directly subordinate to Emperor Uroš or to Vukašin. Vukašin died in the Battle of Maritsa (1371) against the invading Ottoman Empire, and southern Serbian provinces became nominal Ottoman vassals. Four months later, Uroš died. The lords could not agree on the rightful ruler; they dismissed Prince Marko, the son of Vukašin, and conflicts started between the nobles within a year. An assembly was held in 1374 without any success since the nobles were unable to agree on whether Marko or Prince Lazar would head the Serbian confederation as the Serbian king and the state continued as before, fragmented and without central authority.

Between 1345 and 1373, four Serbian monarchs held the title of emperor (tsar). The full title was initially Emperor of the Serbs and Greeks, later Emperor of the Serbs, Greeks and Bulgarians in Serbian and basileus and autokrator of Serbia and Romania ["the land of the Romans"] in Greek. This title was soon enlarged into "Emperor and Autocrat of the Serbs and Greeks, the Bulgarians and Albanians".The Serbian Empire was ruled by two monarchs: Stefan Dušan (r. 1346–1355) and Stefan Uroš V (r. 1355–1371). Two other claimants of the title ruled in Thessaly, Central Greece.

Vukašin Mrnjavčević (Serbian Cyrillic: Вукашин Мрњавчевић, pronounced [ʋukǎʃin mr̩̂ɲaːʋtʃeʋitɕ] ; c. 1320 – 26 September 1371) was King of Serbia as the co-ruler of Stefan Uroš V from 1365 to 1371. He was also a nobleman. Principal domains of Vukašin and his family were located in southern parts of medieval Serbia and northwestern parts of the modern region of Macedonia. He died in the Battle of Maritsa in 1371 with his brother, Jovan Uglješa.

In folk tradition, Vukašin is referred to as a usurper and, wrongly, the murderer of Tsar Uroš. He was often considered de facto ruler of Serbian Empire during the reign of Uroš.

Marko Mrnjavčević (Serbian Cyrillic: Марко Мрњавчевић, pronounced [mâːrko mr̩̂ɲaːʋt͡ʃeʋit͡ɕ] ; c. 1335 – 17 May 1395) was the de jure Serbian king from 1371 to 1395, while he was the de facto ruler of territory in western Macedonia centered on the town of Prilep. He is known as Prince Marko (Macedonian: Kрaле Марко; Serbian Cyrillic: Краљевић Марко, Kraljević Marko, IPA: [krǎːʎeʋit͡ɕ mâːrko]) and King Marko (Macedonian: Kрaл Марко; Serbian Cyrillic: Краљ Марко; Bulgarian: Крали Марко) in South Slavic oral tradition, in which he has become a major character during the period of Ottoman rule over the Balkans. Marko's father, King Vukašin, was co-ruler with Serbian Tsar Stefan Uroš V, whose reign was characterised by weakening central authority and the gradual disintegration of the Serbian Empire. Vukašin's holdings included lands in north-western Macedonia and Kosovo. In 1370 or 1371, he crowned Marko "young king"; this title included the possibility that Marko would succeed the childless Uroš on the Serbian throne.

On 26 September 1371, Vukašin was killed and his forces defeated in the Battle of Maritsa. About two months later, Tsar Uroš died. This formally made Marko the king of the Serbian land; however, Serbian noblemen, who had become effectively independent from the central authority, did not even consider to recognise him as their supreme ruler. Sometime after 1371, he became an Ottoman vassal; by 1377, significant portions of the territory he inherited from Vukašin were seized by other noblemen. King Marko, in reality, came to be a regional lord who ruled over a relatively small territory in western Macedonia. He funded the construction of the Monastery of Saint Demetrius near Skopje (better known as Marko's Monastery), which was completed in 1376. Later, Marko became an Ottoman vassal and died on 17 May 1395, fighting against the Wallachians in the Battle of Rovine.

The House of Crnojević (Serbian Cyrillic: Црнојевић, pl. Crnojevići / Црнојевићи) was a medieval Serbian noble family that held Zeta, or parts of it; a region north of Lake Skadar corresponding to southern Montenegro and northern Albania, from 1326 to 1362 CE, then 1403 until 1515.

Its progenitor Đuraš Ilijić was the head of Upper Zeta in the Medieval Kingdom of Serbia and Empire (r. 1326–1362†), under Stefan Dečanski, Dušan the Mighty and Stefan Uroš V. Đuraš was killed in 1362 by the Balšić family, the holders of Lower Zeta (since 1360); Zeta was in the hands of the Balšići under nominal Imperial rule until 1421, when Serbian Despot Stefan Lazarević was given the province by Balša III (1403–1421). The family fought its rivals following the murder of Đuraš, and the Crnojevićs controlled Budva from 1392 until 1396, when Radič Crnojević was murdered by the Balšićs. They are mentioned again in 1403, as vassals of the Republic of Venice, taking power in their hereditary lands.