It is known that Catherine was of Bosnian origin, but her parentage is disputed.
Some believe that Catherine was the daughter of Vladislav Kotromanić and his wife Jelena Šubić.
Others [citation needed] believe she was the second daughter of Stephen II, Ban of Bosnia, and his third wife Elizabeth of Kuyavia.
If Catherine was a daughter of Stephen, she was the sister of Queen Elizabeth of Hungary; if she was a daughter of Vladislav, she was sister of King Tvrtko I of Bosnia.
[citation needed] Catherine was married in 1361 (or 1362) to Hermann I, Count of Cilli (Celje).