Despoina Helena and Lazar's brother Stefan seized power and began negotiating a marriage between her eldest daughter and Stephen Tomašević, the elder surviving son of King Thomas of Bosnia.

[3] The intent was to consolidate an alliance against the threat of the expanding Ottoman Empire, which had already reduced the Despotate of Serbia to a strip of land governed from the Smederevo Fortress.

[8] Maria's queenship did not last long either; in 1462, her husband made a fatal decision of refusing to pay tribute to the Ottomans, who started preparing an attack which ended the independent Kingdom of Bosnia.

Following the Ottoman invasion in May 1463, the royal family appears to have decided to split and flee towards the neighbouring Croatia and Dalmatia in different directions to confuse and mislead the attackers.

Bosnian Franciscan friars retrieved them and headed towards Ragusa, but were intercepted in Poljice by Ivaniš Vlatković, a local nobleman and friend of the queen, who refused to let them pass without her permission.

[7] The Republic of Venice also expressed interest in Maria's heirloom, but she was gravely offended in August when Venetian authorities miserly tried to question the authenticity of the relics.

[12] She regretted the transaction after the Hungarian king Matthias Corvinus offered her three or four towns in exchange for the relics, but her attempt to have Ivaniš retrieve them in late August failed.

They soon instructed the government of Spalato to recommend moving her to Sebenico (now Šibenik, Croatia) or to an island on the grounds of poor living conditions in the monastery, with the intention of permanently removing her from their territory.

[18] In October 1484, Queen Maria approached the Sublime Porte to ask for the sultan's help in reclaiming a third of her paternal grandfather's deposit in Ragusa, which she insisted had not been returned to her father.

Shortly afterwards she called to Sharia court the monks of Xeropotamou Monastery, alleging that one of them stole money from her aunt Kantakouzene while in her service, but could not prove this.

The tribute had been paid by Ragusa to Serbian rulers since the reign of Stefan Dušan, but the income was ceded to the Monastery of Saint Archangels Michael and Gabriel in Jerusalem.

He wrote that Queen Maria married a sipahi with whom she had no children, but went so far as to claim that she was captured by the Turks in Bosnia and forced into the marriage, which is evidently untrue.