With the collapse of the Great Moravian Empire at the turn of the 10th century, upper River Nitra region found itself on the edge of the territory belonging to the sphere of the Old Hungarian tribal union – the Hungarians. Troops advancing from the south stopped in front of the region of Upper Nitra. It was Upper Nitra, together with Bojnice and other neighbouring areas, that formed the ancestral property of the Poznan (later the Hont-Poznan) family, who, like other local nobles, entered the service of the Old Hungarian chieftains.
The oldest written record from 1113 in the charter of the Hungarian King Coloman for Zobor Abbey mentions Bojnice as an area beneath the castle. It describes the boundary of the abbey property of the later Opatovce nad Nitrou from Bojnice in Latin:
„de suburbanis Baimoz est terminus fervidus fons et postea est terminus lapis“
i.e., ‘from the Bojnice “suburbanians” (here: people living beneath the castle), the landmark is the hot spring, and then the landmark is the stone’.
Charter of the Zobor Abbey from 1113 – the first indirect written mention of the castle in Bojnice. (photo: Martin Hlauka).
The establishment of a complex fortification system in stone form on the Bojnice travertine mound did not occur until the second half of the 13th century, in connection with the change in policy of the Hungarian ruler, Béla IV, after the devastating Mongol invasion (1241–1242). In this period, an important era of the construction of castles or smaller fortifications by the magnates in the whole territory of Upper Hungary began. The existence of Bojnice Castle is directly documented in writing in 1299. Three years later (1302) the castle is clearly mentioned as a functioning landlord's residence and the centre of the manor.
Until the end of the 13th century, Bojnice Castle belonged to the important Hont-Poznan aristocratic family, whose members owned estates mainly in the Hontian and Nitra counties. However, Matthew III Csák of Trenčín’s expansion deprived them of the castle in 1297. The already powerful medieval “oligarch’s” boldness was strengthened by the unexpected death of King Andrew III of Hungary in 1301. It is said that on this occasion Matthew III Csák had a linden tree planted in front of the entrance to Bojnice Castle. The “King Matthias Linden Tree” still grows there today as a mute witness.
In the chaos after the death of the Hungarian monarch, there was no one to cross Matthew III Csak’s path during his ascension. Thus, he gradually took control of the territory of 14 counties and 60 castle dominions. Only his death in 1321 put a definitive end to his ambitions. He died without a male descendant in his residence at Trenčín Castle. Subsequently, Bojnice Castle was seized together with other castles of Matthew III Csák by the Hungarian ruler Charles Robert.