She was married to Manfred of Sicily 2 June 1259, after the death of his first wife Beatrice of Savoy in 1257 and his own rise to the throne on 10 August 1258. D. J. Geanakoplos notes that this marriage was surprising, considering Manfred's father
Frederick II had been in an alliance with
John III Vatatzes, the late ruler of the Empire of Nicaea, but "one must consider that conquest of the
Byzantine Empire had been a traditional Norman aim for almost a century, and that Manfred was now in a strong enough position in Italy to discard his father's alliance and to look to those who could assist him in his ambitions for Balkan domination." Few details of how this marriage was arranged have come down to us. "It would be of interest," Geanakoplos observes, "to know who took the initiative to promote the marriage alliance; whether Manfred's marriage preceded that of
William of Achaea to
Anna, another daughter of Michael II; and, most important, whether Manfred's Epirote possessions were secured from Michael II actually as a result of conquest or as a dowry." Manfred had captured
Dyrrhachium and its surrounding area within the following two years. Michael II still had a territorial claim at the city but at the time was preparing to besiege
Thessalonica. Helena's
dowry included all rights to Dyrrhachium and its surrounding area along with the island of
Corfu. Corfu was the only clear territorial gain for Manfred. == Imprisonment ==