Zeta under the Balšići

The Balšići are mentioned in a charter issued in 1360 to the Republic of Ragusa by Emperor Stefan Uroš V, as provincial lords in the Zeta region.[2] According to Mavro Orbin (l. 1563–1614), 'A poor Lord Balša', said to be 'kin to Nemanja' held only a village located between the Adriatic and Bojana river during the rule of Emperor Dušan (r. 1331–55) but after the death of the Emperor and following years under his son, Uroš V, by 1362 had taken over Lower Zeta, after removing vojvoda Đuraš Ilijić of Upper Zeta who had held the position since around 1326 (since Stefan Dečanski). Balša, together with his three sons Stracimir, Đurađ I and Balša II, conquered Upper Zeta and the towns of Skadar, Kotor and Bar. Đurađ I ruled until 1378 and Balša II until 1385.[2]

Đurađ's rule extended from around 1362 to 1378. He had forged an alliance with King Vukašin Mrnjavčević, having married his daughter Olivera, until Mrnjavčević's fall at the Battle of Maritsa (1371). Đurađ I ran Zeta as a modern ruler of the time. Zeta's institutions were functioning well, while the coastal towns enjoyed considerable autonomy. Commerce was well developed and enhanced by the existence of Zeta's currency, the dinar. Đurađ I allied with his neighbors Prince Lazar Hrebeljanović of Serbia, Ban Tvrtko I Kotromanić of Bosnia, Prince Nikola I Gorjanski and King Louis I of Hungary, to defeat the ambitious Nikola Altomanović in 1373. In spite of this, the defeated and blinded Altomanović found refuge in Zeta until his death. While he was battling in the south of Kosovo, Đurađ's younger brother Balša II married Komnina, a close cousin of Emperor Stefan Dušan's wife, Jelena. Through the marriage, Đurađ II received a generous dowry in land, including Avlona, Berat, Kanina, and some additional strategically important regions. Upon the division of Altomanović's lands (in Herzegovina), the Balšićs took the towns of Trebinje, Konavle and Dračevica. Subsequent dispute over these towns led to a conflict between Zeta and Bosnia, led by Ban Tvrtko I. The fight was eventually won by Bosnia, supported by Hungary, after Đurađ's death in 1378.

In 1378, following Đurađ's death, his brother Balša II became the King of Zeta. In 1382, King Tvrtko I conquered Dračevica, and built the town later known as Herceg-Novi. According to some documents, Balša was of Vlach origin.[3] Both Tvrtko I and Balša II aspired to ascend to the throne of the Nemanjić dynasty.

During his rule, Balša II's could not maintain the control of the feudal lords as his predecessor did. His power was strong only in region around Skadar, and in the eastern part of Zeta. The most prominent feudal lords who did not recognize Balša's rule was the House of Crnojević, who were consistent encouraged by the Venetians to rebel against him.

Balša II needed four attempts to conquer Drač, an important commercial and strategic center. Defeated, Karl Thopia appealed to the Turks for help. Turkish forces led by Hajrudin Pasha inflicted heavy damage to Balša II's forces and killed him at a major Battle of Savra near Lushnjë, in 1385.

The successor of Balša II, Đurađ II Stracimirović Balšić, ruled Zeta from 1385 to 1403; he was Balša's nephew and son of Stracimir. He also had difficulties controlling the local feudal lords, with no control over the fiefs of the entire Upper Zeta. In addition, the feudal lords around Onogošt (Nikšić) accepted the Venetian protection. The most prominent of those lords was Radič Crnojević, who controlled the area between Budva and Mount Lovćen. Moreover, a number of Arbanas feudal lords, particularly Lekë Dukagjini and Paul Dukagjini joined the conspiracy against Đurađ II.

With this in mind as well as the constant danger from the Turks, Đurađ II maintained strong family ties with the Serbia's main lord of the time, Prince Lazar. To help Prince Lazar defend the Serbian lands from Ottoman invasion, Đurađ II sent his troops along with Ban Tvrtko I Kotromanić's forces (with whom he had a dispute over Kotor) to meet the Ottoman army at Kosovo Polje. Despite Sultan Murad I's death, the Serbian army suffered a defeat at the epic Battle of Kosovo in 1389. According to the sources, Đurađ II did not participate in the battle, being in Ulcinj in Southern Zeta.

In later years, Đurađ II played skillful diplomatic games to enhance the rivalry between the Ottomans and the Venetians. To that purpose, he offered Skadar to both hoping that eventually he would be able to keep it. After two years of fighting, Turks and Venetians agreed to leave it to Đurađ II, who was neutral in the conflict. Similarly, the rivalry between Venetians and Hungarians brought a benefit to him. After a serious defeat of his forces by Turks near Nicopolis, the Hungarian King Sigismund gave him the title of Prince of Arbania and the control over the islands of Hvar and Korčula.

In the feud between Đurađ Branković and his uncle, Stefan Lazarević (son of Prince Lazar), who later received the title of Byzantine Despot, Đurađ II sided with Stefan. Due to Đurađ's support, Stefan defeated Turkish forces led by Đurađ Branković in the Battle of Tripolje on Kosovo Field in November 1402.

In 1403, Đurađ II's 17-year-old son, Balša III, inherited the throne of Zeta after his father died as a consequence of the injuries he suffered in the Battle of Tripolje. As he was young and inexperienced, his main advisor was his mother Jelena, a sister of the Serbian ruler, Stefan Lazarević. Under her influence, Balša III declared Orthodox Christianity as the official state religion; however, Catholicism was tolerated.

Balša III continued the policies of his father. In 1418, took Skadar from the Venetians, but lost Budva. In the following year he made an unsuccessful attempt to recapture Budva. Afterwards he went to Belgrade to ask for help from Despot Stefan, but never returned to Zeta.