in the campaign “Muscovite–Ukrainian War (1658–1659)”
When covert methods of destabilization proved insufficient, the tsardom moved to open military invasion. The regular Muscovite army tried to subdue the Hetmanate by force, which ended in catastrophe at Konotop. The imperial historian Soloviev admitted: "The flower of the Muscovite cavalry, which had made the fortunate campaigns of '54 and '55, perished in a single day… Never again was the tsar of Muscovy able to field such a strong host"[1].