Petras Jonaitis Mantigirdaitis, was a prominent noble of the Grand Duchy of Lithuania. in 494, Mantigirdaitis was sent on the diplomatic mission to negotiate peace with the Grand Duchy of Moscow and marriage of Helena of Moscow to where?
Petras Jonaitis Mantigirdaitis:  Grandson of Petras Mantigirdaitis, he first appeared in written sources in 1476 and reached his career high in 1490s when he was Voivode of Trakai (1490–97) and Grand Marshal of Lithuania (1491–97). Petras Jonaitis Mantigirdaitis:  Chronicler Marcin Bielski described that Alexander Jagiellon was crowned and blessed as the new Grand Duke of Lithuania by the Bishop of Vilnius in 1492. Petras Jonaitis Mantigirdaitis:  Then Mantigirdaitis presented Alexander with a naked sword and a reminder that Alexander was elected to be a just ruler. Petras Jonaitis Mantigirdaitis:  In 1494, Mantigirdaitis was sent on the diplomatic mission to negotiate peace with the Grand Duchy of Moscow and marriage of Helena of Moscow to Alexander to end the First Muscovite–Lithuanian War. Helena of Moscow: Helena Ivanovna of Moscow (Russian: Елена Ивановна ; Lithuanian: "Elena" ; Polish: "Helena Moskiewska" ; 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. Helena of Moscow:  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. Helena of Moscow:  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.
Alexander