Her sister Gaitelgrima married Guaimar III of Salerno, while her brothers, Landulf and Pandulf, became princes respectively of Benevento and Capua.
In 1028, she and the younger son, Manso, seized the Amalfitan throne and expelled Sergius and John, who fled to Constantinople.
It is indicative of her power that Manso received no titles, not even from Byzantium, as his father and brother had before him.
He deposed his brother and reconciled with Maria, who subsequently joined him in blinding Manso and exiling him to the fortress of Castelluccia on Li Galli.
This act of cruelty outraged the Amalfitans, who deposed both of them and accepted the rule of Guaimar IV of Salerno.