Mladen was not popular in Bosnia and had fought bloody but losing wars against the Serbian Kingdom (under Stephen Uroš II Milutin), and the Venetians (to whom he lost Zadar in 1313), along with numerous internal opponents of his regime.

Until 1319 Mladen's II army had already entirely retreated from Bosnia, as he had found himself stuck in numerous troubles and conflicts with revolting cities in Dalmatia.

Near the end of 1321, he ordered Stephen II to act from Bosnia supported by Ban Ivan Babonić from Slavonia, encircling and isolating Croatia.

Due to the fact that he wanted to get revenge and get rid of the Šubićs, this was useful to him for the time being, since he could then rule Bosnia uninterrupted without incursions from Dalmatia, and practically entirely by himself as Charles I would be too far away to watch his every move.

Mladen II fell back to Klis Fortress and waited for Charles I to come, blindly believing that he would somehow retain his power because of Šubić's loyal service during King's ascension to tron.

[4][5] Immediately after the death of Serbian King Stefan Uroš II Milutin in 1321, he had no problem in acquiring his lands of Usora and Soli, which he fully incorporated in 1324.

He helped his uncle Vladislav of Syrmia to regain all Serbia, but after the fall of Ostrvica at Rudnik at the hands of Stefan Dečanski, there was no more point in supporting him during the struggles for the Serbian throne, so he took Usora and Soli for himself.

He offered Stephen the hand of his wife's distant relative, Elizabeth of Kuyavia, daughter of Duke Kazimierz III of Gniewków and received from the King as a gift with the marriage the lands to the west formerly held by Mladen I Šubić Bribirski and Usora and Soli in the north formerly held by Stephen Dragutin and his son, Vladislav II of the Nemanjić.

The Hungarian king Charles I Robert had asked Stephen II again, around 1323, to join the new Ban of Slavonia Nikola Omodijev and launch a joint offensive against Nelipić in Croatia.

The expedition eventually had little success, so Mikac sent a portion of his army to Bihać which would serve as defence against Nelipić's possible counterattacks and retreated to Hungary.

Ban Stephen II gained territories, expending his realm to the coast by annexing space between mouths of the Cetina and the Neretva rivers, and all in between Bosnia main proper and the coast, namely vast expanses of karst poljes of Livanjsko, Duvanjsko and Glamočko, which will from that point on be known as Završje (also "Western Sides", Bosnian: Zapadne Strane), until territorial reconfiguration under Ottomans.

Petar raised a rebellion, wishing either more autonomy or total independence and the eventual restoration of the conquered territories to Serbia.

Hungarian King Charles Robert managed to replace his supporter, but it would take until 1336 for the final dispute to be resolved in the Catholic Church's favour.

Pope Benedict XII lost all patience and eventually accepted the offer of Prince Nelipac of Croatia in 1337, who not only wanted to restore Bosnia under Croatian control, but also desired personal revenge on Stephen II Kotromanić for the past troubles that he had caused him.

In addition, Serbia wanted a reason to involve itself in a conflict, for its King desired revenge for the losses in the Bosnian war against the Serbs, so Ban Stephen abandoned the thought.

After the final peace between the Bosnian Ban and the Papacy, the Catholic Church started to grow in influence rapidly throughout Bosnia in 1340–43.

The Roman Catholic monks had constructed numerous monasteries in Usora and Hum and baptised a large number of Bosnia's heretics on their way to Ston in the Republic of Ragusa.

In 1342, Hungarian King Charles Robert died and so did Stephen II's past ally, Mikac of Slavonia in 1343.

Venice was just waging war against Prince Nelipac, so it only agreed to arm and help build up Bosnia's military, but begged Stephen II not to move against Hungary without it.

He annexed several cities from the Nelipić family of Croatia, but left them the two largest until Stephen II gave the Cetina region back.

The Hungarian King subsequently issued a proclamation in Zagreb accepting Ban Stephen II as a member of his family and returned with his 30,000 men to Hungary before attempting to reconquer the coastal cities taken by the Venetians.

Ban Stepen's Bosnia was weaker than the Serbian Empire, so he asked Venice, as a mutual ally, to act as a mediator.

In the Christmas of 1349 Bosnia's Ban moved quickly, proceeding all the way across Konavli which he raided heavily until he reached the Bay of Kotor.

Using timber and rock he blockaded all major roads in Bosnia and slowly withdrew his forces to forests and mountains, using impervious topography of his realm and forts to defend against advancing invader.

Losing control over the conflict, Ban Stephen II retreated with his most trusted men to the most unreachable mountains of Bosnia.

After creating a strong foothold with forces in Bosnia, Dušan sent a portion of his army on raiding quests towards Cetina and the other to Croatia towards Krka, while he returned with the rest of his troops to Serbia to resolve new conflicts that the Byzantines stirred in Macedonia.

Both failed siege of Bubovac and attempt to catch up with Ban Stephen II eventually compelled Dušan to abandon Bosnia and order his troops to retreat.

Politically and militarily savvy Ban, now proved himself foresighted too, as he will soon start witnessing first traces of Dušan's Empire demise, while he regained full control over his realm, Bosnia.

The same year he gave his sister or niece, Marija, in marriage to Count Ulrich of Helfenstein, which was sanctioned by the Hungarian King.

Here is an excerpt of the documents edict' copies:[9] да имамо и дрьжимо до конца свиета непомачно.