Kaloyan of Bulgaria
Viola's father's origins are disputed by historians. Chronicler Jan Długosz noted that she was originally from Bulgaria. A more popular hypothesis about Viola's parentage was given by Władysław Dziewulski, who stated that she could be the daughter of either Kaloyan of Bulgaria or his successor Boril, but this theory has been challenged by Wincenty Swoboda. Jerzy Horwat put forward another hypothesis, under which Viola could have been a daughter of either King Béla III from his second marriage to Margaret of France or his son and successor, Emeric. Today, historians widely favor that the origins of Viola are unknown.