Childhood and youth
From Tales of the Life and Courage of the Pious and Great Prince Alexander found in the Second Pskovian Chronicle, circa 1260–1280, comes one of the first known references to the Great Prince:
"By the will of God, prince Alexander was born from the
charitable, people-loving, and meek the Great Prince Yaroslav, and
his mother was Theodosia. As it was told by the prophet Isaiah:
'Thus sayeth the Lord: I appoint the princes because they are
sacred and I direct them.'
"... He was taller than others and his voice reached the people
as a trumpet, and his face was like the face of Joseph, whom
the Egyptian Pharaoh placed as next to the king after him of
Egypt. His power was a part of the power of Samson and
God gave him the wisdom of Solomon ... this Prince Alexander: he
used to defeat but was never defeated ..."
Born in Pereslavl-Zalessky, St. Alexander was the second son of Prince Yaroslav Vsevolodovich and of Rostislava Mstislavna, daughter of the Kievan Rus' Prince Mstislav Mstislavich the Bold (died 1228). Alexander seemed to have no chance of claiming the throne of Vladimir. In 1236, however, the Novgorodians summoned him to become knyaz (or prince) of Novgorod and, as their military leader, to defend their northwest lands from Swedish and German invaders.
According to the Novgorod Chronicle written in the 14th century (more than a century after the events it recorded), the Swedish army had landed at the confluence of the rivers Izhora and Neva, Alexander and his small army suddenly attacked the Swedes on 15 July 1240 and defeated them. The Neva battle of 1240 saved Novgorod from a full-scale invasion from the West. Because of this battle, 19-year-old Alexander gained the sobriquet "Nevsky" (which means of Neva). This victory, coming just three years after the disastrous Mongol invasion of the Rus' lands of the North West, strengthened Alexander's political influence, but at the same time it worsened his relations with the boyars. He would soon have to leave Novgorod because of this conflict.
No non-Russian contemporary source mentions this supposed battle. The Chronicle identifies the alleged Swedish commander as "Spiridon" – while names after Saint Spyridon appear in both West and East, it is by far much more common in Orthodox lands than Scandinavia. Furthermore, Sweden had stood on the brink of war with Norway ever since the Norwegians' infamous Värmland expedition in 1225. Relations improved only after the Treaty of Lödöse in 1249, which was forged by the new Swedish strongman Birger Jarl.
Before the treaty, Norway remained an ally of the Folkungs, giving them refuge and providing men and arms.
In this situation, it seems unlikely that Sweden could have been able to organize a major expedition against Novgorod. Swedes are not known to have carried out any other military campaigns between 1222 and 1249, making the claims about their forceful appearance at the Neva with Norwegians as their allies in 1240 seem questionable.
After the Germans and Estonians invaded Pskov, the Novgorod authorities sent for Alexander. In spring of 1241 he returned from exile, gathered an army, and drove out the invaders. Alexander and his men faced the Livonian heavy cavalry led by the bishop of Dorpat (Hermann, brother of Albert of Buxhoeveden). The Rus' force met the enemy on the ice of Lake Peipus and defeated the German knights and the Estonian infantry during the Battle of the Ice on 5 April 1242.
Alexander's victory marked a significant event in the history of Russia. Foot soldiers of Novgorod had surrounded and defeated an army of knights, mounted on horseback and clad in thick armour. Nevsky's great victory against the Livonian Order apparently involved only a few knights killed rather than the hundreds claimed by the Russian chroniclers; decisive medieval and early-modern battles were won and lost by smaller margins than those seen in contemporary mass conflicts.