CEVAP:

The Kievan principality declined further because of disputes, conflicts between regional princes, invasions from Asia together with the collapse of commercial ties between Byzantium and Europe. During the 12th century, the Crusades opened new trade routes from Europe to the Orient through the Crusader states of the Middle East. However, the decisive blow to this first stage of the Eastern civilization was the Mongol invasion in the first half of the 13th century.