Kammala jumla mai zuwa: Zaporizhian Cossacks ya zama mai ƙarfi musamman a farkon kwata na karni na 17 a ƙarƙashin jagorancin hetman Petro Konashevych-Sahaidachny, wanda ya ƙaddamar da kamfen mai nasara a kan Tatars da Turks. Tsar Boris Godunov ya jawo ƙiyayya ga Cossacks na Ukrainian ta hanyar ba da umarnin Don Cossacks don fitar da duk Cossacks na Ukrainian da ke tserewa daga tashin hankali na 1590s. Wannan ya ba da gudummawa ga shirye-shiryen Cossacks na Ukraine don yaƙi da shi. A cikin 1604, 2000 Zaporizhian Cossacks sun yi yaƙi a gefen Commonwealth na Poland-Lithuania, da kuma shawarar su ga Tsar (Dmitri I), a kan sojojin Muscovite. A watan Satumbar 1604, Dmitri I ya tara sojoji 2500 maza, daga cikinsu 1400 Cossacks ne. Kashi biyu cikin uku na waɗannan "Cossacks", duk da haka, a zahiri fararen hula ne na Ukraine, 500 ne kawai ƙwararrun Cossacks na Ukraine. A ranar 4 ga Yuli, 1610, 4000 Ukrainian Cossacks sun yi yaƙi a cikin
Yaƙin Klushino, a gefen Jam'iyyar Polish-Lithuanian. Sun taimaka wajen kayar da rundunar sojojin Muscovite-Swedish da kuma sauƙaƙe mamayar Moscow daga 1610 zuwa 1611, suna hawa zuwa Moscow tare da Stanisław Żółkiewski.