Moscow was a growing power in the seventeenth century and after loosing the war of 1632-1634 it was craving revenge. The reign of Alexei Mikhailovich (1645-1676) was a time of great change for Moscow and they began to modernize the army. Following the complete destruction of the Muscovite army at Konotop (1659), it became clear that further reforms were needed. In order to deal with ever increasing European enemies, more Western European style units were formed, foreign officers were hired to train and lead the troops, the strength of the army was increased, and the level of engineering and artillery was improved.
All of this made Moscow an extremely dangerous enemy. The 1654-55 campaign in Lithuania was especially successful for the Muscovite army, as it was able to nearly conquer the entire duchy. The victory of the Polish Lithuanian Commonwealth at Polonka (1660) was possible only thanks to the Polish veteran units under Czarniecki. The Muscovites were also badly beaten by the Cossacks under Yurij Chmielnicki at Chudniv that same year, but overall, the armies of Moscow began to improve. In the 1670s and 1680s Moscow fought a series of wars with both the Tatars and the Ottomans and was able to extend its power.
In Moscow, the tsar ruled with complete freedom. The tsarist autocracy allowed one man to make all of the decisions, while the nobles served as advisors. The tsar also controlled the Orthodox Church and could call upon it to serve the interests of the state when needed. Rebellions against the Tsar were not uncommon, the most famous of which was lead by Stepan Razin. Razin’s rebellion, though eventually ending in failure, spread through the lower Don and engulfed the entire Volga region. In the end, the authority of the Tsar was never in doubt and he was able to enforce his will on an ever-growing region.