864-876

The Duke Domagoj, "the severest" Croats' duke (pessimus Sclavorum dux), as described by Venetian chronicler Ioannis, rules over the parts known today as southern Dalmatia and lower Herzegovina. He waged naval warfare against Venetians and Arabs around the Italian city of Bari cca. 871. It was the Byzantine Empire that (probably) stood behind a conspiracy to overthrow him. However, Domagoj, having discovered the conspiracy, drastically punished the conspirators, executing them all, including the conspirator-turned-informer. 

910-928

Croatian King Tomislav routed Hungarians and pushed them across the Drava river. Also, he defeated Bulgarians and protected Serbs from the Bulgarian yoke (926.). Tomislav rules over the greater part of what is now Bosnia and Herzegovina, a fact unwillingly accepted even by Serbian historians: "..During the first half of the X century until the 30ies, political boundary of the Croatian kingdom was, in all probability, drawn across mountain wreath comprising of the mountains Zelengora, Lelija, Treskavica, Jahorina, Romanija, Ozren i Zvijezda (essentially, this is deeply into the eastern part of contemporary Bosnia and Herzegovina)"

X-XI

In Humac, a village in the vicinity of the Herzegovinian town Ljubuski, St. Michael's church was built and a stone tablet positioned within the church. The tablet, known as the Humac tablet, is the oldest monument of Croatian (and, generally, any Slavonic) literacy on the soil of Bosnia and Herzegovina. Written in Bosnian/Croatian Cyrillic, with a few Glagolitic letters, it is now preserved in the museum of Franciscan monastery in Humac.

1137.

Bosnia was joined to Hungary. From that time, the Croatian-Hungarian kings held the title "rex Ramae" (tributary to Neretva), which meant Bosnia. It then became a special dukedom (ducatus) of Bela's son Ladislav.

1154.-1163.

Banus (the governor) Boric, a Croat from Grabarje area nearby Slavonski Brod, and a descendant from Berislavici Graberski familiy, is mentioned in Bosnia. His descendants are thought to be Bosnian bans and kings Kotromanici. During his time, Bosnia gains a kind of an autonomy within the borders of the Croat-Hungarian state.

1164.-1167.

Bosnia subdued to Byzantium.

1165.-1204

Ban Kulin reigned in Bosnia. He was the founder of the Bosnian ruling family Kotromanic. He established the ruler's chancellery, helped Bela III against the Byzantium, living in good relations with his neighbours and the Pope. The people have not forgotten Kulin's reign. During his reign, the heretical movement of "krstjani" (often mistakenly referred to as Bogumils) spread. He was their protector but later renounced the movement.

Mature Medieval Period: Integration, Expansion and Dissolution (1180 - 1463)
 

1189.
Kulin made a contract with Dubrovnik in accordance with which merchants from Dubrovnik obtained complete freedom of trading within Bosnia and great influence over the Bosnian economy.

1199. and 1200.
The first news about the heretics in Bosnia reached Rome. The expelled "patareni" (heretics) asked for protection from Kulin.

1203.
The Pope sent deputies to Bosnia to investigate the religious situation there, whereupon the "krstjani" took a vow of obedience to the Holy See. Ban Kulin was mentioned for the last time that year, leaving behind him a son of unknown name (it is possible he was called Stjepan).