Battle of Shelon The Battle of Shelon ( ) was a decisive battle between the forces of the Grand Duchy of Moscow under Ivan III ( r . 1462 – 1505 ) and the army of the Novgorod Republic , which took place on the Shelon River on July 14 , 1471 . Novgorod suffered a major defeat and ended with the " de facto " unconditional surrender of the city . Novgorod was absorbed by Muscovy in 1478 . Background . The clash between the Muscovy and the Novgorod Republic was a continuation of the conflict between them going back into the late 14th century . This particular episode was caused by Novgorod ' s violation of the Treaty of Yazhelbitsy ( 1456 ) signed between Grand Prince Vasily II and the Novgorodian delegation headed by Archbishop Evfimy II . In particular , the treaty limited Novgorod ' s ability to conduct its own foreign affairs and gave the Grand Prince of Moscow more control over the city ( he controlled the city ' s seals and became the court of higher instance for the Novgorodian courts ) . When the Novgorodians turned to Poland – Lithuania for help in limiting Moscow ' s growing power , Ivan III and the metropolitan accused them not only of political treachery , but of attempting to abandon Eastern Orthodoxy and go over to the Catholic Church . A draft treaty between Novgorod and the Grand Duke of Lithuania and King of Poland , Casimir IV Jagiellon ( r . 1440 – 1492 ) , said to have been found in a cache of documents after the battle of Shelon , made it clear that the Lithuanian Grand Prince was not to interfere with the election of the archbishop of Novgorod or the Orthodox faith in the city ( by building Catholic churches in the city for example . ) The battle . The battle took place in the morning of July 14 on the left bank of the Shelon River , which flows into Lake Ilmen southwest of Novgorod . It is believed to have taken place about 30 km from the mouth of the river and just to the east of the town of Soltsy , possibly , near the village of Skirino . The location indicates that the Muscovite army was advancing on Novgorod along the western shore of the lake to come up on the city from the southwest . After an accidental encounter of the Muscovite forces ( around 5 , 000 men ) under the command of Prince Daniel Kholmsky ( Daniel of Kholm ) with the army of Novgorod ( 20 , 000 to 40 , 000 men ) , the badly organized army of Novgorod was not able to withstand the pressure of the princely forces . Indeed , the " Novgorodian Fourth Chronicle " reports that Feofil , Archbishop - Elect of Novgorod , ordered his cavalry to not attack the Muscovites , but only the Pskovian forces , thus limiting their room to maneuver . The Battle of Shelon lasted for two hours and ended with Novgorod ' s defeat . According to Muscovite sources , more than 12 , 000 Novgorodians were killed during the battle and the subsequent pursuit . Some 2 , 000 men were taken prisoners . It is , however , difficult to say how accurate these figures are ans the size of the Novgorodian army at this time are almost impossible to determine , and the number seems quite high given that the city of Novgorod itself probably had a population of only about 40 , 000 people , although the army could have been drawn from the rural population as well . That being said , the numbers may have been inflated to add to the Grand Prince ' s prestige and cast Novgorod in an even worse light . Aftermath . On July 24 , Ivan III executed the Novgorodian commander , Dmitry Isakevich Boretsky , one of the Boretsky clan which , led by Marfa Boretskaya , had championed the city ' s opposition to Moscow . In the longer term , the defeat at Shelon severely weakened the Novgorodian Republic . According to some sources , Ivan III confiscated significant amounts of land from the archiepiscopal administration and several of the largest monasteries immediately after the battle ( although most sources date these confiscations to 1478 ) , thus weakening the independence of the Novgorodian church . He also returned to the city several times in the 1470s and arrested important boyars or entire boyar clans . However , he only took direct control of the city - state in January 1478 after further strained relations with Archbishop Feofil and Novgorodian boyars led him to send his armies against the city in the winter of 1477 – 1478 .