the time, this area was under the rule of the Mongol khanate of the Golden Horde

http://www.historytoday.com/ole-j-benedictow/black-death-greatest-catastrophe-ever#sthash.hVY6px39.dpuf—“At the time, this area was under the rule of the Mongol khanate of the Golden Horde. Some decades earlier the Mongol khanate had converted to Islam and the presence of Christians, or trade with them, was no longer tolerated. As a result the Silk Road caravan routes between China and Europe were cut off. For the same reason the Black Death did not spread from the east through Russia towards western Europe, but stopped abruptly on the Mongol border with the Russian principalities. As a result, Russia which might have become the Black Death’s first European conquest, in fact was its last, and was invaded by the disease not from the east but from the west.

The epidemic in fact began with an attack that the Mongols launched on the Italian merchants’ last trading station in the region, Kaffa (today Feodosiya) in the Crimea. In the autumn of 1346, plague broke out among the besiegers and from them penetrated into the town. When spring arrived, the Italians fled on their ships. And the Black Death slipped unnoticed on board and sailed with them.

– See more at: http://www.historytoday.com/ole-j-benedictow/black-death-greatest-catastrophe-ever#sthash.hVY6px39.dpuf”—