Kacsics was the name of a gens ("clan") in the Kingdom of Hungary. According to some historians, they might have been a descendants of a Croatian noble family of Kačić, dukes of Omiš.[1] [2] Their possessions were located around Szécsény on the Ipoly River (Slovak: Ipeľ). A member of the gens, Simon took part in the murder of Queen Gertrude of Merania (24 September 1213) and therefore King Andrew II of Hungary confiscated his possessions.
The Kacsics gens divided into four branches by the end of the 13th century. The powerful Szécsényi family ascended from one of its branches.
The members of the gens accepted the supremacy of Máté Csák, one of the most powerful oligarchs of the kingdom, around 1300; only one of them, Thomas Szécsényi became the partisan of King Charles I. Consequently, the king granted him his relatives' possessions following his victories over the oligarch.