Helena Ivanovna of Moscow (; ; ; 19 May 1476 – 20 January 1513) was daughter of Ivan III the Great, Grand Prince of Moscow, and an uncrowned Grand Duchess of Lithuania and Queen of Poland as she would not convert from Eastern Orthodoxy to Catholicism. Her childless marriage to Grand Duke of Lithuania and later King of Poland Alexander Jagiellon was a constant source of tension between the Grand Duchy of Moscow and the Grand Duchy of Lithuania. Instead of guaranteeing peace, Helena's marriage gave her father Ivan III an excuse to interfere in Lithuanian affairs accusing Alexander of mistreating Helena and repressing Orthodox believers. This became the pretext to renew the Muscovite–Lithuanian Wars in 1500. The war ended with a six-year truce in 1503; the Grand Duchy of Lithuania lost about a third of its territory. Despite political tensions and religious differences, the marriage was a loving one and the royal couple was close. After her husband's death in 1506, Helena wanted to return to Moscow but was not allowed. When she planned to run away, she was arrested and reportedly poisoned.
Biography
Early life and marriage plans
Helena, possibly named after her great-grandmother Empress Helena Dragaš, was the eldest surviving child of Ivan III, Grand Prince of Moscow, and his second wife Sophia Palaiologina, niece of the last Byzantine Emperor Constantine XI Palaiologos. Helena was an older sister of Grand Prince of Moscow Vasili III of Moscow. Little is known about Helena's childhood in Moscow, but it is known that she was literate and very attractive.
When Helena was eight, Jan Zabrzeziński and Ivan Yuryevich Patrikeyev discussed a marriage between Helena and one of the sons of the Polish King Casimir IV Jagiellon. 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. In 1489, Frederick III, Holy Roman Emperor, was looking for a Muscovite alliance in the Austrian–Hungarian War and against Polish claims to the Kingdom of Hungary, which were based on inheritance of Polish queen Elizabeth of Austria. The Emperor proposed to have Helena and her younger sister Theodosia marry into his family, but Ivan III refused and instead suggested the Emperor's widowed son Maximilian I. The Emperor entertained the proposal, but did not take it too seriously. At the same time Sophia's brother Andreas Palaiologos in consultation with Filippo Buonaccorsi advised her to seek an alliance with Poland. Nevertheless, an alliance between the Emperor and Moscow without a marriage agreement was concluded in August 1490. 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.
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. John I Albert became King of Poland while Alexander Jagiellon became Grand Duke of Lithuania. The Muscovite army was successful and a peace with Moscow, guaranteed by a marriage between Alexander and Helena, became a priority for Lithuania. An "eternal" peace treaty was concluded on 5 February 1494. 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 – the lost area was estimated to be approximately . 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).