Hermann of Dorpat in the context of Bishopric of Dorpat

The Battle on the Ice, also known as the Battle of Lake Peipus, took place on 5 April 1242. It was fought on the frozen Lake Peipus when the united forces of the Republic of Novgorod and Vladimir-Suzdal, led by Prince Alexander Nevsky, emerged victorious against the forces of the Livonian Order and Bishopric of Dorpat, led by Bishop Hermann of Dorpat.

The outcome of the battle has been traditionally interpreted by Russian historiography as significant for the balance of power between Western Catholicism and Eastern Orthodox Christianity. It is disputed whether the battle should be considered a "crusade" or not, and whether it therefore represented a significant defeat for the Catholic forces during the Northern Crusades, thus bringing an end to their campaigns against the Orthodox Novgorod Republic and other Rus' territories. Estonian historian Anti Selart asserts that the crusades were not an attempt to conquer Rus', but still constituted an attack on the territory of Novgorod and its interests.