(Russian parliament's) call for vengeance and reclamation of lost lands, the Russian army sallied west. Hostilities The Russian army that crossed the Lithuanian border in early October 1632 had been carefully prepared and was under the experienced command of Mikhail Borisovich Shein, who had previously defended Smolensk against the Poles during the 1609–1611 siege. Several towns and castles fell as the Russians advanced, and on 28 October 1632 (the same day that the historic town of Dorogobuzh was taken), Shein moved to begin the siege of Smolensk. Former Polish estimates of the size of the Russian forces varied from 25,000 through 30,000 to 34,500, with 160 artillery pieces. Recent research on 17th-century Russian archive documents showed that the size of the Russian army was 23,961. Compared to former Russian armies, Shein's army was significantly modernised. Dissatisfied with their traditional formations of musket-equipped infantry (the streltsy), the Russians looked to foreign officers to update the equipment and training of their troops based on the Western European model of regulars, dragoons, and reiters. Eight such regiments, totaling 14,000 to 17,000 men, comprised part of Shein's army. Siege of Smolensk Commonwealth forces in Smolensk were composed of the Smolensk garrison (about 1,600 men with 170 artillery pieces under the command of the Voivode of Smolensk, Aleksander Korwin Gosiewski), strengthened by the local nobility, which formed a pospolite ruszenie force of about 1,500 strong. The city's fortifications had also recently been improved with Italian-style bastions. Shein constructed lines of circumvallation around the fortress. Using tunnels and mines, his forces damaged a long section of the city wall and one of its towers. Russian heavy artillery, mostly of Western manufacture, reached Smolensk in December 1632 with even heavier guns arriving the following March. After a preliminary artillery bombardment, Shein ordered an assault, which was repulsed by the Polish defenders. Nonetheless the siege was progressing; Smolensk's fortifications were being eroded, and the defenders were suffering heavy casualties and running out of supplies. By June 1633, some soldiers started to desert, and others talked of surrender. Despite these difficulties, the city, commanded by Deputy Voivode Samuel Drucki-Sokoliński, held out throughout 1633 while the Commonwealth, under its newly elected King Władysław IV, organised a relief force. The Sejm had been informed about the Russian invasion by 30 October 1632, and, starting in November, had discussed the possibility of relief. However, the process was delayed until the spring of