However, feudal fragmentation remained important in Bosnia and the Bosnian nobility held significant power, exercising it at the Stanak meetings where members deliberated on matters such as election of the new king or queen and coronations, foreign policy, sale or cession of territory, contracting and signing treaties with neighboring countries, and military issues.

The Ottoman Empire annexed portions of eastern Bosnia in the 1440s and 1450s and went on to conquer Hum, by then renamed to Herzegovina, with the last fortress, Novi, falling in December 1481.

The Banate of Bosnia existed until 1377,[6][7][8] when it was elevated into a kingdom with the coronation of Tvrtko I[9][10] following the death of the last Serbian Emperor from the Nemanjić dynasty, which had no heir to the throne in 1371.

Tvrtko had the strongest claim to the royal title at that time, and even if he had no practical means to rule Serbia, it allowed him to elevate Bosnia to a kingdom, as this would imply more formal independence.

[19] The right to take part in the sessions of the stanak was enjoyed by every Bosnian knez, from magnates to petty lords, collectively known as vlastela, but the ultimate authority belonged to the highest nobility.

[17] The Stanak enjoyed power and authority on all matters, including election of the new king or queen and coronation, foreign policy, sale or cession of territory, contracting and signing treaties with neighboring countries, and military issues.

After defeating Altomanović, they divided his lands, except for his littoral districts of Dračevica, Konavle, and Trebinje, which were seized by Đurađ I Balšić, the Lord of Zeta.

In the last months of his reign, Tvrtko devoted himself to solidifying his position in Dalmatia and to plans for taking Zadar, the only Dalmatian city that had evaded his rule.

Soon thereafter Dabiša submitted to Sigismund and resigned Croatia and Dalmatia to the Hungarian king and, with the agreement of his vassals, recognized him as his feudal overlord as well as heir designate to the Bosnian throne.

In return, as evident from a treaty issued in July 1394, Sigismund included Dabiša among the highest ranking Hungarian officials and named him ispán (count) of Somogy.

Not willing to engage the united nobility in war, Sigismund withdrew; the death of his wife Mary, heir of Hungary and cousin of Dabiša, made his position too precarious to attack in Bosnia, as did the defeat by the Ottomans at the Battle of Nicopolis.

[43] It seems that Helen's family, the Nikolić, attempted to take further advantage of their royal relations and free themselves from subordinacy to the House of Kosača to become immediate vassals of the monarch.

[47] Following a few minor disputes with the maritime republics of Venice and Ragusa over Konavli and Pomorje, Tvrtko gained recognition as the legitimate king from both states.

[47] The hostilities continued until the end of November, with Tvrtko retreating southwards with his noblemen and resisting Hungarian attacks, which enabled Ostoja to reestablish control over Central Bosnia.

In December 1422 Tvrtko signed a beneficial trade treaty with the Republic of Venice and discussed plans for joint military action against Sigismund in Dalmatia.

In 1432, Stefan Lazarević's successor Đurađ, Sandalj, and the Ottomans helped Radivoj, the elder illegitimate son of the long-deceased Ostoja, to lay claim to the throne and take control of much of the country.

Throughout his reign, Thomas waged a war with the Serbian Despotate over the lucrative mining town of Srebrenica and its surroundings, in addition to (or in conjunction with) multiple conflicts with his father-in-law.

Having failed to expand into Croatia proper, Thomas turned again to the east in 1458, arranging a match between his son Stephen Tomašević and the Serbian heiress Helena.

This alliance could have easily deposed Tvrtko II in Radivoj's favor if they wished, but it appears that their only goal was to weaken and divide Bosnia for their own future benefit.

King Tvrtko II died in September 1443. childless, having expressed a wish to be succeeded by his politically inactive and until then rather obscure cousin Stephen Thomas, Radivoj's younger brother and likewise an illegitimate son of Ostoja.

And while Thomas' decision to convert was forced political maneuvering, albeit founded in sound reasoning with the saving of the realm on his mind, he also committed himself to demonstrate his devotion by engaging in religious prosecution against his recent fellow co-religionist, thus eventually proving his conversion to be detrimental to the Kristjani.

[69][70] Later, toward the end of 1449 and the beginning of 1450, in a public relations stunt,[68] he changed it to Herzog of Saint Sava, Lord of Hum, Grand Duke of Bosnia, Knyaz of Drina, and the rest.

On 21 May 1466, old and terminally ill duke dictated his last words, recorded in a testament, and bypassing Vladislav he condemned him by saying that it was him who "brought the great Turk to Bosnia to the death and destruction of us all".

[78] Just before death of Sultan Mehmed II, Vlatko tried one more push to the heart of Bosnia, but abandoned by his allies his venture ended in disaster, after which he completely and finitely withdraws to his fortress in Novi.

In November 1481, Ajaz-Bey of the Sanjak of Herzegovina besieged Novi, however, just before 14 December 1481 Vlatko gave up resisting, and agreed with the Ottomans to move with his family to Istanbul.

[86] Despite the religious hesitancy of the duke, by his death, the Bosnian Church had lost its foothold in Donji Kraji, since his heirs were increasingly referred to as committed Catholics.

After Stephen Thomas started persecuting Bosnian Church followers, they responded in the traditional stronghold in Visoko and in 1450 demolished the Franciscan monastery in Mile.

[66] Important mining towns like Fojnica, Kreševo, Olovo, Srebrenica, Dusina, Kamenica, and Deževice began to be mentioned in contemporary sources during Tvrtko I's reign.

[92][93][full citation needed] A particularly large caravan trade happened on 9 August 1428 between Podvisoki and Ragusa, when Vlachs committed to Ragusan lord Tomo Bunić that they would deliver 1500 modius of salt on 600 horses.

[99][full citation needed] The most important customs posts were in Drijeva, Vrabač, Deževice, Podvisoki, Trebinje, Foča, Goražde, Borač, Višegrad, Olovo, and Srebrenica.