First Congress of Vienna

The First Congress of Vienna was held in 1515, attended by the Holy Roman Emperor, Maximilian I, and the Jagiellonian brothers, Vladislaus II, King of Hungary and King of Bohemia, and Sigismund I, King of Poland and Grand Duke of Lithuania. Vladislaus II made a Habsburg-Jagiellon mutual succession treaty with Emperor Maximilian in 1506. It became a turning point in the history of central Europe. After the death of the childless king Louis II at the Battle of Mohács against the Ottomans in 1526, the Habsburg-Jagellion mutual succession treaty ultimately increasing the power of the Habsburgs and diminishing that of the Jagiellonians.

Maximilian had been supporting Vasili III of the Grand Duchy of Moscow against the Jagiellonian rulers of Lithuania, Poland, Hungary and Bohemia, to advance the Habsburg claims to the succession in Hungary and Bohemia. The Jagiellonians had been facing simultaneous threats on all fronts, from the Emperor, the Russians, the Teutonic Order under Albert of Prussia, and the Crimean Tatars. The city of Smolensk fell to the Russians in 1514, and Maximilian planned a congress to cement his claims in central Europe. However, Lithuanian and Polish forces decisively defeated the Russian army at the Battle of Orsha on 8 September 1514, changing the balance of power.

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