Having defeated Northeastern Russia, the Mongol-Tatars moved to Novgorod, but, not reaching it for some hundred kilometers, they turned back. Novgorodians said that God saved them. But modern people should understand that there are other reasons here, and not God's providence.
One of the most widespread versions of the salvation of Veliky Novgorod is the fear of the Mongol Khan Batu to get bogged down in the Novgorod lands, because spring was coming, and with it the thaw. Considering that it was the 13th century, there was no normal road infrastructure at that time. This version deserves the right to take place. Although, today, some researchers say that it was very cold that year, and one could not expect an early thaw.
The second version is a decrease in the combat effectiveness of the Mongol-Tatar army. Moving through the territory of Russia and constantly taking battles with the Russian army, the Tatars could not help but suffer losses that were not replenished with fresh forces. In addition, having approached Novgorod, the Mongol army would have faced the squad of the Novgorod prince Alexander Yaroslavovich (the future hero of the Battle of the Neva and the Battle of the Ice), which had not previously participated in battles on the territory of Russia with the Tatars, and therefore remained fully operational. And Novgorod itself was perfectly fortified and did not suffer from the princely feuds that took place on the territory of Russia.
There is also a third version - the rich Veliky Novgorod, who traded with many countries, simply bought off the Mongol-Tatars. After all, the latter went to Russia with one goal - to obtain booty, or, as they said then, for tribute. And they got it. And why destroy the city, which will then again lay out the ransom on demand in order to avoid ruin. And Batu understood this perfectly.
Be that as it may, but Veliky Novgorod withstood at that terrible time, and continued to live. Russia also lived, gradually recovering and rising from the ruins, gathering strength into an iron fist to repel enemies.