The 1370s was a decade that began on 1 January 1370 and ended on 31 December 1379. It is distinct from the decade known as the 138th decade which began on January 1, 1371 and ended on December 31, 1380.
Mamai was a powerful military commander of the Golden Horde, who resided in the western part of this nomadic state, which is now the Southern Ukrainian Steppes and the Crimean Peninsula. He split apart from Khans of the Golden Horde, trying to establish his own state.