Later in 1603, the commonwealth crossed the frontier with a small force of 4,000 Poles, Lithuanians, Russian exiles, German mercenaries and Cossacks from the Dnieper and Don Rivers at the beginning of the Polish–Muscovite War. Although King Sigismund III Vasa supported the intervention, the Poles were too preoccupied with conflicts with Sweden and the Ottoman Empire to begin another war with Russia. Some members of the "szlachta" supported False Dmitri I with their own forces (and money), expecting to be rewarded afterward.