Historical development of the medieval noble kindred of the Babonići can be traced from the beginning of the 13th century. The period of the highest social and political influence of the Babonić kindred was the beginning of the 14th century. At that time they were the most powerful noble family within the area of the medieval Kingdom of Slavonia, mostly in the areas south of the river Sava. Their estates were placed south of the river Sava up to the mountain Kapela, and between the river Vrbas in the east and the river Kupa in the west. The last scions of the kindred died out in the middle of the 19th century. Even though the kindred of the Babonići was undoubtedly particularly powerful, it was not the subject that attracted some greater interest of historians. This PhD thesis analyzes the period of their rise to power and the one when they were at their peak. It then follows their history until the end of the 14th century when their social role was highly diminished by changes happening all over the Kingdom of Hungary and Croatia at that time. The work discusses the origin of the noble kindred and the political actions of its members, its influence on local circumstances, but also on wider relations within the Kingdom of Hungary-Croatia. Furthermore, the structure of the noble kindred is discussed, as well as its functioning. The thesis will also deal with the issues connected with the economic base of the kindred’s power; it will try to establish the location of its estates and major centers. The main goal of the thesis is to give the most complete description possible of the functioning and the development of the noble kindred of the Babonići, as one of the most important noble kindreds of the medieval Kingdom of Slavonia. Due to the lack of written sources it is very difficult to define the origin of the kindred of Babonići. Nevertheless, the very fact that the first known members of the Babonići kindred are usually named comes in the preserved written sources, it is possible to connect their origin with the duty of the župani (counts) of the medieval Gora county in southern Slavonia. The close affiliation between the Babonići and the royal Arpad dynasty, mainly king Andrew II, as well as the political influence of the Babonići in the wider area of the medieval kingdom of Slavonia shows their exceptional social status, much higher than that of any other noble kindred from the Gora county in the first half of the 12th century. Hence, the starting point of the later Babonići kindred was most likely somewhere in the southern parts of the medieval Gora county, i.e. somewhere on the southern slopes of the Zrinska Mountains, as they are called today, towards the valley of the river Una. According to the archeological excavations which confirmed the existence of the settlements as early as the end of the 11th and beginning of the 12th century, it is very much possible that the starting point of the Babonići kindred was the Zrin castle or the nearby Gorička castle. The members of the Babonići kindred climbed slightly upwards on the social and political scale in the period from the middle of the 13th up to the end of the 14th century. In the same time they managed to expand their estates. The peak of political ascend of the Babonići kindred was the second decade of the 14th century, the period in which the two members of the kindred, count Stephen V and John I, were bans of Slavonia. In that time the Babonići held a great number of strong castles and many estates in the areas of the present-day Banovina, Kordun, Žumberačko-samoborski gorjeMountains, but also in the areas of the present-day Moslavačka Mountain/gora, as much as in the valley of the river Vrbas. After the political and armed conflicts with ban Mikac, the exponent of the king Charles Robert, in the middle of the third decade of the 14th century the Babonići were heavily defeated under the Stjeničnjak castle. This defeat was very soon shown to be worse than it looked in the beginning. Not only had the Babonići lost their political influence but they had also lost numerous castles and estates, all except those in the valley of the river Una. In spite of that, in the second half of the 14th century, the Blagaji, descendants of the Babonići, managed to restore political, economical and social influence of the kindred. The areas of the central and lower valley of the river Una, except the castles Zrin, Dubica and Bihać, became the center of the estates of the Blagaji in the following decades up to the middle of the 16th century, i.e. the time when these areas were occupied by the Ottomans. Considering the inner social structure of the Babonići kindred, it can be said that this noble kindred was organized on the agnatic principle in which the basic connection between the members of the kindred was blood relationship. At the end of the 14th and in the beginning of the 15th century the final breakup of the Babonići kindred occurred. The kindred was broken up into several noble families, but only the sons of count Dujam of Blagaj survived. Therefore, in the following decades, only the counts of Blagaj can be traced in the preserved written sources. The members of the noble kindreds of the medieval Kingdom of Hungary jointly possessed estates and shared the income from those estates. Furthermore, the collectiveness of the members of noble kindreds was visible in a joint usage of common symbols, such as name and coat of arms, as much as the remembrance of the common ancestor. As can be seen from the preserved written sources, the members of the Babonići kindred were very rarely termed genus or generatio, which was common in the Middle Ages. Most commonly they were named after their fathers or after the most important castle or estate. The coat of arms of the Babonići kindred can be reconstructed from the preserved wax seals from the end of the 13th and the beginning of the 14th century. The main heraldic symbols of their coat of arms were sidelong balks. Nevertheless, in the upper half of the shield on the oldest wax seals there was a golden lion, which was changed in the beginning of the 15th century to rose and bear – the symbols from the coat of arms of the noble Ursini family. Similarly to the other noble kindreds of the medieval Kingdom of Hungary, the Babonići also used their marriage strategies to improve their political positions not only within but also outside the borders of the medieval Kingdom of Hungary. In the period of the peak of their political and social influence the members of the Babonići kindred married the noble women of the influential noble families outside the medieval Kingdom of Hungary, such as the counts of Görz and Tyrol, or the counts of Ortenburg. Nevertheless, after the middle of the 14th century the Babonići more often married the women from the magnate families of the medieval Kingdom of Hungary, such as the counts of Krbava. In the period of the greatest political and economical influence the Babonići had a great network of their servants and familiares who served them in many aspects. They were the wardens of their estates, but also legates, the castellani of the castles. They followed their lords in their military campaigns as the members of the banderium. Of course, the Babonići had their holy places such as the Altar of the Holy Cross in the chapel of Saint Nicholas placed inside the monastic complex of the Cistercian abbey in Topusko. Furthermore, the Babonići were the patrons of many churches and monasteries placed in the areas of their political influence. Even more, the Babonići encouraged the development of trade on their estates by building many market places under/at the foot of their fortified cities. In spite of the fact that this doctoral thesis tried to give answers to various scientific questions connected to social, political, economical, political and religious life of the Babonići from the beginning of the 13th to the end of the 14th century, many questions still have to be answered. Therefore, further scientific research has to be directed towards the relations of the Babonići and other religious orders; such as the Franciscans and Dominicans who had their monasteries in the areas of political influence of the Babonići kindred. Of course, a special study of the historical development of the counts of Balaj in the 15th and 16th century should also be conducted. Even more, the Ottoman raids on the estates of the Blagaji that started in the late 15th and lasted up to the middle of the 16th century have to be investigated. In order to discuss these and many other questions, further research has to be done not only on the published medieval sources but also on archival sources mostly kept in the archives in Budapest and Vienna. All this research demands much more time, as well as much more funding. Therefore, it is postponed for some future time.