At the same time the Rus' princes rebelled against his rule, removing a valuable source of tax income from Mamai.

Mamai was defeated at the famous 1380 Battle of Kulikovo, at which a Muscovy-led coalition of Rus' princes scored a pyrrhic victory.

[a] Mamai raised more troops and prepared another operation to subdue these rebellious Rus' principalities once more.

[2] No details of the battle remain but Tokhtamysh, who probably had a larger army,[citation needed] won a decisive victory.

[1] According to the earliest version of the "Chronicle Tale" (Letopisnaia povest’), Tokhtamysh informed Muscovite prince Dmitry Donskoy that he had defeated their mutual enemy Mamai.