Complex sentence: He fought on the Russian side in the campaigns of voyevodas Romodanovsky and Trubetskoy and took part in the Battle of Konotop where he commanded around 7,000 Cossacks, where Russian and Bezpaly Cossack trops were defeated.
Split into simpler sentences: He fought on the Russian side in the campaign of voyevodas Romodanovsky and Trubetskoy. Bezpalyy took part in the Battle of Konotop (he commanded a regiment of around 7,000 Cossacks) in which the Muscovite forces and their allies were defeated.