The first mention of the term Malorossia dates back to Byzantine ecclesiastical documents in 1335. The two Greek terms Megálē Rhōssía and Mikrà Rhōssía were used to refer respectively to the Orthodox metropolises (ecclesiastical regions, much like dioceses in the Catholic world) encompassing the Northern and Southern Principalities of Rus’. Here, the intended meaning was largely a matter of size and population. There is some evidence to support that the terms would be more accurately translated as Outer and Inner Rus’, but the Greek is fairly clear here.
Politically at this time, the principalities were effectively divided and controlled by the Jochid Horde, but were already beginning to evolve. The Northern States that would make up the core of Russia were largely dominated by forest and under less direct Mongol control — being more tributary states, while the Southern States that would become Ukraine were steppe lands that saw more Mongol influence at the time. More to the point, the rising principality of Vladimir-Suzdal in the North seized the terms to claim preeminence over Kyiv and the South. The Princes of Moscow (which was founded later in 1348) would then adopt this interpretation, the culmination of which we will see in the next installment.