Background. In the late 1370s and early 1380s, Timur helped Tokhtamysh assume supreme power in the White Horde against Tokhtamysh's uncle Urus Khan.After this Tokhtamysh united the White and Blue Hordes, reuniting the Golden Horde, and launched a massive military punitive campaign against the Russian principalities between 1381 and 1382, restoring Turco-Mongol …