The Battle of Orsha was fought on 8 September 1514, between the allied forces of the Grand Duchy of Lithuania and the Kingdom of Poland, under the command ofHetman Konstanty Ostrogski; and the army of the Grand Duchy of Moscow under Konyushy Ivan Chelyadnin and Kniaz Mikhail Golitsin. The Battle of Orsha was part of a long series of Muscovite–Lithuanian Wars conducted by Muscovite rulers striving to get ancient Balts lands which were at first time invaded by former Kievan Rus'.

According to Rerum Moscoviticarum Commentarii by Sigismund von Herberstein, the primary source for information on the battle, the much smaller army of Poland–Lithuania (under 30,000 men) defeated a force of 80,000 Muscovite soldiers, capturing their camp and commander. These numbers and proportions have been disputed by modern historians.

On 8 September 1514, shortly after dawn, Ivan Chelyadnin gave the order to attack. The Muscovite forces attempted to outflank the Lithuanians and Poles by attacking their flanks, which were manned by Polish, Lithuanian light hussar and Tartar troops. One of the pincers of the attack was commanded by Chelyadnin personally, while the other was led by Prince Bulgakov-Golitsa. The initial attack failed, and the Muscovites withdrew toward their starting positions. Chelyadnin was still confident that the odds, almost 3:1 in his favor, would give him the victory. However, preoccupied with his own wing of the Muscovite forces, he lost track of the other sectors and failed to coordinate a defense against the counterattack by the Lithuanian light and Polish heavy cavalry, which until then had been kept in reserve.

The Lithuanian and Polish light horse and Tartars attacked the overstretched center of the Muscovite lines in an attempt to split them. At the crucial moment the Lithuanian-Polish cavalry seemed to waver, then went into retreat. The Muscovites pursued with all their cavalry reserves. The Lithuanian Tartars and Polish cavalry, after retreating for several minutes under chase from the Russians, suddenly turned to the sides. The Muscovite cavalry now found themselves confronted by artillery concealed in the forest. From both sides, Polish and Lithuanian forces appeared and proceeded to surround the Muscovites. Ivan Chelyadnin sounded retreat, which soon became somewhat panicky. The Muscovite forces were pursued by the army of theGrand Duchy of Lithuania for five kilometres.

The Muscovite defeat is often attributed to repeated failures by Ivan Chelyadnin and Golitsa to coordinate their operations.

Sigismund von Herberstein reported that 40,000 Muscovites were killed.

According to accounts in Polish chronicles, 30,000 Russians were killed and an additional 3,000 were taken captive, including Ivan Chelyadnin and eight other commanders. The forces of the Grand Duchy of Lithuania and Kingdom of Poland seized the Muscovite camp and all 300 cannons. Upset at word of the massive defeat, Grand Prince Vasili III allegedly remarked that "the prisoners [were] as useful as the dead".

Aftermath

  Polish Hussars during the Battle of Orsha (1514)

Ostrogski's forces continued their pursuit of the routed Russian army and retook most of the previously captured strongholds, including Mstislavl and Krychev, and the advancement of the Russians was stopped for four years. However, the Lithuanian and Polish forces were too exhausted to besiege Smolensk before the winter. This meant that Ostrogski did not reach the gates of Smolensk until late September, giving Vasili III enough time to prepare defense.

In December 1514, Hetman Konstanty Ostrogski triumphantly entered Vilnius. To commemorate the victory, two Orthodox churches were erected: the Church of the Holy Trinity and the Church of Saint Nicholas, which remain among the most impressive examples of Orthodox Church architecture in Lithuania. Immediately after the victory, the Polish–Lithuanian state started to exploit the battle for its propaganda aimed at other nations in Europe, with the intent of improving the image of Lithuania-Poland abroad. Several panegyrical accounts of the battle were sent to Rome. "The Polish message was similar to Bomhover's: the Muscovites are not Christians; they are cruel and barbaric; they are Asians and not Europeans; they are in league with Turks and the Tatars to destroy Christendom".

Impressed by the scope of the Lithuanian and Polish victory, Maximilian I, Holy Roman Emperor, started peace negotiations with the Jagiellons in Vienna. On 22 July 1515, final agreements for peace were made and the broad coalition against Lithuania and Poland ceased.

The war between the Grand Duchy of Lithuania and Grand Duchy of Moscow lasted until 1520. In 1522 a peace was signed, under the terms of which Lithuania was forced to cede to Moscow about a quarter of its possessions within the historical baltic lands, including Smolensk. The latter city was not retaken until almost a century later, in 1611.

After the peace agreement of 1522, the Grand Duchy of Lithuania tried to attack Russia one more time, but major military conflicts were settled for around 40 years.