[4] Elizabeth was baptised in the Eastern Orthodox faith of her mother, an arrangement that aroused consternation in the Roman Catholic milieu of Celje.
[6] In June 1448, the two parties reached an agreement on the division of spheres of interest, sealed by Elizabeth's betrothal to Ladislaus, John Hunyadi's firstborn son.
The wedding was set to 6 December 1453,[11] with the stipulation that should the marriage fail to materialize because any fault attributable to Branković, the latter's castles and other estates in Hungary would be transferred to Hunyadi and his sons.
In the fall of 1453, in fact, Elizabeth's father fell out of favor with king Ladislaus, and Hunyadi took advantage of the situation to dissolve the alliance with the Celjes which limited his autonomy of action in Hungary.
[13] By February 1455, however, Ulrich was back in power, and Durad Branković was instrumental in renewing the alliance between his son-in-law and Hunyadi in order to secure a common front against the Ottoman threat.
[14] He was sent to the royal court in Buda where Ulrich now resided as regent, while Elizabeth settled in the Hunyadis' estates; the two young spouses thus served mostly as hostages between their respective families.