She was a daughter of Ivan III, Grand Prince of Moscow, and she was never crowned as she would not convert from Eastern Orthodoxy to Catholicism.

[6] At the time Poland was looking for allies in the Polish–Ottoman War (1484–1504), which broke out after the Ottomans captured Kiliya and Bilhorod-Dnistrovskyi, two major ports on the Black Sea.

At the same time Sophia's brother Andreas Palaiologos in consultation with Filippo Buonaccorsi advised her to seek an alliance with Poland.

The alliance lost its relevance after the Peace of Pressburg (1491) and further proposals to marry Helena off to Maximilian or his son Philip did not gain much support.

[7] In August 1492, shortly after the death of Polish King Casimir IV Jagiellon, Ivan III of Moscow attacked the Grand Duchy of Lithuania, launching what would become a series of Muscovite–Lithuanian Wars.

The Muscovite army was successful and a peace with Moscow, guaranteed by a marriage between Alexander and Helena, became a priority for Lithuania.

The agreement marked the first Lithuanian territorial losses to Moscow: the Principality of Vyazma and a sizable region in the upper reaches of the Oka River[9] – the lost area was estimated to be approximately 87,000 square kilometres (34,000 sq mi).

[10] A day after the official confirmation of the treaty, Alexander Jagiellon was betrothed to Helena (the role of the groom was performed by Stanislovas Kęsgaila).

Alexander wanted to add that if she wished so herself, Helena could convert, but Ivan III adamantly rejected the amendment.

[12] Ivan III left Helena with detailed instructions on how to behave, whom to invite for lunch, where to pray (she was prohibited from visiting Catholic churches).

The wedding ceremony was officiated by Catholic Wojciech Tabor, Bishop of Vilnius, and Orthodox Foma, priest who accompanied Helena from Moscow.

[14] Reportedly Helena did not bring much dowry (jewelry, three icons, silver and gilded dishes, expensive fabrics, furs, a carriage with horses) and Alexander did not gift her with lands after the wedding (he did so only in August 1501).

For example, it seems that Queen Elisabeth of Austria was purposefully late to her son's wedding and kept pressuring her schismatic daughter-in-law to convert.

[22] Around 1498, Joseph Bolharynovich, Metropolitan of Kiev, and Wojciech Tabor, Bishop of Vilnius, attempted to persuade Helena to support a church union as it was envisioned at the Council of Florence – the Orthodoxs would retain their traditions, but would accept the pope as their spiritual sovereign.

[23] Helena's situation became further complicated when John I Albert died in June 1501 and Alexander was elected as the new King of Poland in October 1501.

Polish nobles, including Bishop Erazm Ciołek and Cardinal Frederick Jagiellon, discussed the issue of royal divorce.

Nevertheless, a six-year truce was concluded; the Grand Duchy of Lithuania lost about 210,000 square kilometres (81,000 sq mi) or a third of its territory.

The tension between Lithuania and Moscow lessened as the new Grand Prince wanted to consolidate his power without starting another war.

[29] Despite his worsening condition, Alexander called Seimas in Lida so that he could transfer the Grand Duchy of Lithuania to his brother Sigismund I the Old.

The King was hastily evacuated to Vilnius, further weakening his health, while Michael Glinski organized defense and won the Battle of Kletsk.

[29] Rumors circulated that Helena aided rebellious Michael Glinski who defected to Moscow, but the charge lacks proof.

[31] It is unknown what happened to Helena's money she left with the Franciscans as there is no record that Sigismund, who was relieved to hear about her death,[5] inherited it.