The exact filiation and even the name of King Manfred's mother, traditionally called Bianca Lancia, are unknown.

1160–1214), the alleged grandfather or father of Manfred's mother, has been lancifer (pikeman) of Emperor Frederick Barbarossa.

[6] Tommaso Tosco also expressed the popular hypothesis that Emperor Frederick II could have had a relationship with both the elder Bianca and her two daughters, one being Manfred's mother.

Niccolò di Jamsilla, who lived at the court of Manfred, mentions that his maternal relatives were the Counts of Agliano,[c] and this may indicate Bianca's father, Bonifazio d'Agliano.

[2][6] Both the chronicles of Salimbene di Adam and Matthew Paris wrote that a "marriage ceremony at the moment of death" (Latin: confirmatio matrimonii in articulo mortis) took place between Bianca Lancia and Emperor Frederick II when she was dying.

As Matthew Paris writes, Bianca wanted to marry for the salvation of her soul and the safety of her children's future,[6][8][9] who were subsequently legitimated (Latin: legitimatio per matrimonium subsequens).

At the same time, Bianca probably died before Frederick II, since the castle of Monte Sant'Angelo, located in the cities of Vieste and Siponto (which, according to King William II of Sicily's will, was the traditional possession of the Queens of Sicily as a "gift morning" after the wedding night and would remain in their possession as a dower), was granted by the Emperor to his son Manfred.

[2][6][7][9] According to a legend recorded by the monk Bonaventure da Lama and found by the historian Pantaleo, Frederick II was jealous of his mistress and locked her in the tower of the Castello Normanno-Svevo in Gioia del Colle.