together with Evert Horn now took charge of providing an auxiliary corps to support the Russian forces commanded by Mikhail Skopin-Shuisky. Although officially the Swedish-Russian alliance was not ratified before July 1609, already in the early spring of 1609 Sweden gathered for this mission to the city of Vyborg (Finnish: Viipuri) in Finland (then part of Sweden) c. 5,000 soldiers, consisting mainly of Finns. A Swedish offensive heading towards Moscow – via Novgorod – began from Vyborg on 11 March 1609. The operation became known as De la Gardie campaign. It was a joint military campaign by the Tsardom of Russia and Sweden during the Polish-Russian War (1605-1618), a.k.a. Polish–Muscovite War or the Dimitriads, lasting officially from April 1609 to 4 June 1610. A combined Russo-Swedish army of about 10,000 soldiers set out from Novgorod in April 1609 and marched towards Moscow, defeating rebel forces and relieving the Siege of Troitse-Sergiyeva Lavra on their way. The De la Gardie campaign was successful against False Dmitry II, dispersing his court in Tushino, a former village and town to the north of Moscow, where Dmitry II maintained an alternative court, challenging the authority of Vasili IV. On 12 March 1610, the Russo-Swedish army broke the rebel siege of Moscow and conquered the city. In the aftermath, some of the Tushino boyars summoned Wladyslaw IV to lay his claim to the Russian throne, while Skopin-Shuisky was poisoned at the behest of his uncle and rival, Prince Dmitry Shuisky. Campaign against Polish–Lithuanian Commonwealth In June 1610, De la Gardie and Dmitry Shuisky departed from Moscow in order to lift the Polish–Lithuanian Siege of Smolensk. The campaign ended with most of De la Gardie's forces defecting to the Polish hetman Stanisław Żółkiewski at the Battle of Klushino in 1610. After this, De la Gardie's remaining army during that summer returned to Vyborg, Finland (then part of Sweden). Aftermath In the Battle of Klushino, after all but 400 of his men rebelled and defected to the enemy, Jacob de la Gardie concluded a truce with Żółkiewski, in exchange for the right of passage with the army to Vyborg and the promise not to serve the Moscow Tsar. The De la Gardie campaign can be considered a prelude to the Ingrian War. References Wars involving Poland Wars involving Russia Wars involving Sweden Warfare of the Early Modern period 1610 in Sweden Conflicts in 1610 Vasili IV of