Relatively favorable development of Northeast Russia (Vladimir - Suzdal land) in the XIIIth- XIVth centuries, which had become the fundamental part of newly united Russian state, depended on the factors, which had taken place before and after the invasion.
The princes of Vladimir - Suzdal land didn't take part in internal wars in the 30s of the XIIIth century, which had noticeably weakened the forces of princes of Chernigov and Smolensk. Princes of Vladimir managed to expand their suzerainty on Novgorod, which had become the more advantageous all-Russian throne, comparing to Kiev and bordering to Steppe Galich, which had later lost their significance.
Unlike Smolensk, Volyn and Chernigov regions, Northeast Russia didn't undergo the pressure of the great Lithuanian principality. Despite the enormous devastation of Northeast Russia by Mongols in the XIIIth century, its princes were considered by the Horde the 'oldest' in Russia. That contributed to transition of All-Russian capital status from Kiev to Vladimir.
During the period of Mongolian invasion North Russia was also confronted by the Baltic expansion. By the XIIth century the population of Baltic lands entered the phase of state formation. At the same time Baltic territories became the object of invasion by German knights, whose crusade campaign had been organized with the Pope of the Rome's bless.
In 1201 the crusaders with monk Albert at the head founded the fortress Riga. The next year the 'Order of sword-bearers' was formed on the occupied territories. In 1212 crusaders placed under command all Livonia and proceeded to conquering Estonian lands, approaching Novgorod borders.
The expansion of crusaders was accompanied by land distribution to German feudal lords and forcing local pagan population into Catholicism. That was the main difference between the policy of the 'Order' and the actions of Russian princes in East Baltic: the latter didn't claim to direct possession of land (being satisfied with tribute only) and didn't force Christianization. In 1234 the prince of Novgorod Yaroslav Vsevolodich, the son of Vsevolod Bolshoe Gnezdo, managed to defeat German knights under Yurievo (Derpt). Two years after, the sword - bearers were crashed by the levy of Lithuanians and Zemgals.
The defeat made the rest of the Order join the greater Teutonic Order in 1237, which by the time had occupied Prussian lands as a result of 'missionary' activity.
The unification of forces of knightly - religious Orders and the formation of Livonian Order had greatly intensified the danger to Great Novgorod and its suburb Pskov. At the same time the threat from the direction of Swedish and German knights had grown.