Alexander Nevsky was prince of Novgorod – today’s Velikiy Novgorod – from 1236 to 1251. In July 1240, he defended Novgorod against the Swedes, who were carrying out a crusade against the Orthodox on behalf of Pope Gregory IX, and defeated them on the Neva – hence his nickname Nevsky. In April 1242 he defeated the advancing Teutonic Order in the Ice Battle of Lake Peipus – today’s Chudsko-Pskovskoye osero – and destroyed the great army. With these two victories he secured the northwestern border of his empire, the border between the Teutonic Order and the Principality of Novgorod remained the border of cultures and denominations for centuries. On the return from a trip to the Mongolian Grand Khan with the request to reduce tribute burdens, Alexander died. He was buried in Vladimir. Alexander became the progenitor of the Moscow dynasty. In 1282, Metropolitan Kirill had Alexander’s life story written down, creating a mixture of princely life and saint’s vita. In 1729, Tsar Peter the Great had the bones transferred to the newly founded Alexander Nevsky Monastery in St. Petersburg. Alexander Nevsky is venerated as a saint in the Russian Orthodox Church for his achievements as ruler, after the discovery of his bones in 1380 he was canonized at the Synod of 1547.
Joachim Schäfer: Article Alexander Nevsky, from the Ecumenical Dictionary of Saints: https://www.heiligenlexikon.de/BiographienA/Alexander_Newskij.htm