Battle on the Ice participant Novgorod Republic
The Battle on the Ice (German: Schlacht auf dem Eise; Russian: Ледовое побоище, Ledovoye poboishche; Estonian: Jäälahing), alternatively known as the Battle of Lake Peipus (German: Schlacht auf dem Peipussee), took place on 5 April 1242. It was fought largely on the frozen Lake Peipus between the united forces of the Republic of Novgorod and Vladimir-Suzdal, led by Prince Alexander Nevsky, and the forces of the Livonian Order and Bishopric of Dorpat, led by Bishop Hermann of Dorpat. 
The battle was significant because its outcome determined whether Western Catholicism or Eastern Orthodox Christianity would dominate in the region. In the end, the battle represented a significant defeat for the Catholic forces during the Northern Crusades and brought an end to their campaigns against the Orthodox Novgorod Republic and other Slavic territories for the next century. The event portrayed in Sergei Eisenstein's historical drama film, Alexander Nevsky (1938), later created a popular but inaccurate image of the battle.
The Novgorodian victory is commemorated today in Russia as one of the Days of Military Honour.