Stjepan Vukčić Kosača (1404– 22 May 1466) was a powerful Bosnian nobleman who was politically active from 1435 to 1466; the last three decades of Bosnian medieval history. During this period, three kings acceded to the Bosnian throne: Tvrtko II, Thomas (Tomaš), Stephen Tomašević (Stjepan Tomašević) and anti-king Radivoj—the older brother of King Thomas—before the country was conquered by the Ottomans.
Stjepan, a son of the Knez of Drina, Vukac Hranić, and Katarina, whose ancestry is unknown, was probably born in 1404. Stjepan's father held hereditary lands in the Upper Drina region. Stjepan was a member of the Kosača noble family and became its chieftain in 1435 when he succeeded his uncle, Duke Sandalj, as Duke of Humska zemlja and the Grand Duke of Bosnia. Stjepan influenced the development of the late Bosnian medieval state more than any other person of his era.
Stjepan supported Radivoj in the line of succession for the Bosnian throne and refused to recognise the ascension of King Thomas, leading to a series of civil wars in the kingdom. During this time, Stjepan added the title herzog () to his intitulation. While searching for help, he aligned himself first with the Ottoman Empire then the Crown of Aragon, and again the Ottoman Empire. The marriage of King Thomas and Stjepan's daughter Katarina temporarily restored peace, but with the death of King Thomas and the ascension of his son and heir, Stephen Tomašević, to the Bosnian throne, peace was finally restored and reconciliation was achieved. This ensured the nobility's, including Herceg Stjepan's, full support of the king and loyalty for the kingdom, which was facing the Ottomans' advancement.
It was Stjepan's herceg title that gave rise to the name of Herzegovina (), which was used as early as 1 February 1454 in a letter Ottoman commander Esebeg wrote from Skopje. In 1470, Herzegovina was separated from the Sanjak of Bosnia and reorganised into the Sanjak of Herzegovina, with a seat in Foča. The name remains in use for the southernmost region of Bosnia and Herzegovina. The town of Herceg Novi in present-day Montenegro, which was founded by Tvrtko I of Bosnia as Sveti Stefan—the name that from the beginning gave way to a name Novi (literally "New"; also known as Castelnuovo in Italian, New Castle in English)—later came to Kosača possession and become their winter seat. During this era, the town was renamed again by adding Stjepan's title herceg (Serbo-Croatian pronunciation of German ''herzog'') to the name Novi, which gave it the current name of Herceg Novi.
Early life and rise
Stjepan Vukčić Kosača, who was probably born in 1404, was the son of Knez of Drina Vukac Hranić Kosača and his wife Katarina, whose ancestry is unknown. Stjepan's father's modest hereditary lands were located in the Upper Drina region, situated in the eastern parts of the Kingdom of Bosnia. It was centered around the village which bears the family name, Kosače, to this day, and is located near Ilovača in the župa of Osanica, some 12 km southwest of Goražde.
In the first two decades of the 15th century, following the death of its first king Tvrtko I, the Kingdom of Bosnia began developing into a less-centralised state with three powerful noble families Pavlović, Vukčić, and Hranić, These families had significant independence in the conduct of their political and economic affairs. They influenced the kingdom's political life to the point at which they had an important role in the accession and succession of the kings, including steering foreign policy. During this period, between 1392 and 1420, several rulers acceded to the Bosnian throne: Stephen Dabiša (1391–1395), Helen (1395–1398), Stephen Ostoja (1398–1404; 1409–1418), Tvrtko II (1404–1409), Stephen Ostojić (1418–1420). Still, Bosnian unity was symbolized in the Bosnian crown, with the royal authority having a place of honor in it, and the Bosnian Church, which was schismatic and independent from both the Catholic and Eastern Orthodox churches. Toward the end of the second decade of the 15th century, however, only Stjepan's uncle Sandalj remained powerful. The state authority became influential again, and the throne was more stable.
Stjepan was the fraternal nephew of one of the powerful Bosnian magnates, Sandalj Hranić, who was the Bosnian Grand Duke and chieftain of the Kosača family. In 1419, Stjepan's uncle Sandalj, who was childless, decided to choose him as his heir. When his father died in 1432, Stjepan inherited his lands in the Upper Drina along with the title Knez of Drina that came with it. Sandalj died on 15 March 1435, and Stjepan succeeded him. Along with Sandalj's noble titles, Stjepan inherited his uncle's lands with all of the attendant obligations, alliances, antagonisms, and conflicting interests. Upon succeeding his uncle, Stjepan became the most powerful magnate in Bosnia.
Citizenship of Dubrovnik
Along with his father and uncles Sandalj and Vuk, Stjepan was admitted into the nobility of the Republic of Ragusa. The republic was an aristocratic maritime state centred on the city of Dubrovnik in South Dalmatia, surrounded since 1326 by the piece of medieval Bosnian state territory known as Primorje.
It was customary for the republic to grant all the principal Bosnian nobility the status of citizenry and the republic's nobility. It was also customary to grant them a palace and a refuge in case of need in Dubrovnik. The City Council granted Stjepan, and his sons Vladislav and Vlatko, citizenship by the charter dated 30 October 1435, a palace and a refuge by the same charter.
Struggle for family inheritance In 1435, a few days after Sandalj's death, legitimate Bosnian king Tvrtko II was forced to flee when the Ottomans put forward Radivoj and assured him support from important Bosnian noblemen Sandalj Hranić and Radislav Pavlović, as well as the Despotate of Serbia. Tvrtko II returned from a two-year exile in Hungary to assume the throne for the second time. Stjepan's takeover from his uncle was met with hope among his neighbours, who anticipated Stjepan would be weak and opportunistically diverted their attention toward his inheritance.
The Holy Emperor King Sigismund wanted to take Hum. He relied on Tvrtko II, who was mostly inactive in his first year of his reign. The Bosnian king then approached Stjepan and assured him of good relations with him, contrary to Sigismund's expectations. This prompted Radislav Pavlović to seek support from the Ottomans and report on the harmonious relations between the king and Stjepan, whose relationship remained close until at least 1440.
Sigismund then turned to Stjepan's other enemies within and outside Bosnia. He successfully sought help from Bosnian noblemen against Stjepan, most of all the Radivojevićs and Vojsalićs, and tried to persuade Dubrovnik to join this coalition. Sigismund also ordered his vassals, primarily Matko Talovac and other Croatian noblemen of the Frankopan family, to attack and retain the land of Hum for him.
Conflicts in Neretva and with Pavlovićs
The first major Bosnian nobility to act was Radislav Pavlović, who engaged Stjepan in the eastern Hum. At the same time, the Vojsalićs and Radivojevićs attacked in the Lower Neretva valley with success. Pavlović acted three days after Sandalj's death on 18 March, and on March 29, he was expected to enter Dračevica. Despite Stjepan being under intense military pressure to the west of the Neretva River from the Hungarian king, his Croatian vassals, and Bosnian allies, Pavlović managed to seize some of Stjepan's lands but was unable to cause serious damage. Radislav then asked the Ragusans to mediate and help him achieve peace. Reluctant to take up the undertaking, they responded by saying Bosnia had many noblemen better suited for the task. Later, the Ragusans led the negotiations and pleaded with both men that a war would bring many "dangers and misfortunes" to them and their subjects, and to Bosnia as a whole. Stjepan demanded that Pavlović cede lands he had taken earlier, but after many missions to both noblemen's courts, the negotiations failed. Other involved Bosnians were Vojsalić's and Radivojević's. Đurađ Vojsalić's attack had produced some results. He took the medieval market town () Drijeva, which also favoured Radivojević, so the coalition between Vojsalić and Radivojević, including Sigismund, who also wanted Drijeva, had conflicting interests. Sigismund asked Dubrovnik to pay him all of the customs tolls and dispatched some of his men to Drijeva to set up the new regimen.
The Republic of Venice also tried to take advantage during the power transfer from Sandalj to Stjepan. Venice unsuccessfully tried to take over the fortress of Novi via neighbouring Kotor and its knez's manoeuvring. Venice thought it could take the town by exerting pressure and influence on the fortress' castellan (governor). Despite the problems, and with some critical moments, Stjepan firmly retained the town.
During these initial struggles, Stjepan had help from the Ottomans, who supported him, and he had Bosnian anti-king Radivoj at his court. Stjepan's situation was challenging but not critical. He invited the Ottomans to Bosnia, and they helped him to overcome all of his adversities.
Acquiring Trebinje
During the initial conflicts for his inheritance, Stjepan Vukčić's most persistent adversary was Duke Radislav Pavlović, against whom the alliance between King Tvrtko II and Stjepan turned. By the end of 1437, Duke Radislav had also fallen out of favour with the Sublime Porte, while Stjepan received a signal from the Sultan to take Trebinje from him. At the beginning of 1438, Radislav Pavlović was in a difficult situation; Stjepan took Trebinje from him and recaptured the town of Jeleč in Upper Podrinje, which Radislav probably seized from Kosača immediately after Sandalj's death. Pavlović's other fortress Klobuk in Vrm was besieged. At that point, the Ragusans told Stjepan he "took revenge on his enemies more than any one of his predecessors". Stjepan's triumph was short-lived, however, as Radislav soon regained the sultan's sympathy. Stjepan had to return Trebinje and other lands he had recently taken from Radislav. Probably through Ottoman mediation, two magnates started negotiations, which lasted until June 1439, ending in peace between the two houses and the renewal of family ties; Radislav remarried Stjepan's sister.
At the beginning of 1440, Radislav Pavlović's situation dramatically changed. Because he owed the Sultan a large sum of money, probably having indebted himself during the campaigns to regain his lands and Trebinje in 1439, the Sultan decided Stjepan Vukčić should repay that debt and, in return, regain Trebinje and its surroundings from Pavlović. In March, Stjepan recaptured Trebinje, which caused war to break out, and in April, new negotiations between the "two main eyes of the Bosnian kingdom", as the Ragusans used to say, pandering to Stjepan's vanity, while trying to mediate between the two noblemen.
While Bosnians fought for personal and petty-proprietary reasons, events around them hinted at problems with far-reaching consequences that would shake the country in the coming years. The Ragusans, guided by logic and observing Ottoman policy, which was quite transparent, advised King Tvrtko II, Duke Stjepan and Duke Radislav to implore the Sultan to lower his impossible demands jointly, and suggested it would be best and easiest if the three men together pay the Sultan thousands of ducats for Radislav's lands. They warned their Bosnian neighbours that friendship bought for money is neither firm nor permanent. They indicated the fate of other regional lords, Serbs, Byzantines, Albanians, who had perished or suffered due to their discord. Neither the fall of Serbia nor increasing Ottoman pressure made the Bosnian lords any less reckless. Stjepan and Radislav continued their quarrel while litigating before the Porte through envoys.