Interdependence and Trade
The Roman Empire divided under the Emperor Diocletian in the late 200s CE.  The Eastern half of the empire became known as the Byzantine Empire, as its new capital was built on the site of the old Greek city Byzantium.   The Byzantine Empire preserved much of the Greco-Roman culture, and helped spread it across a vast region.  The capital city of Constantinople became a crossroads of trade between Europe and Asia.  The interdependent nature of the contact between cultures encouraged cultural diffusion.  The empire's biggest influence was on Russia.  Byzantine missionaries spread the Orthodox Christian religion to Russia, and also adapted the Greek alphabet to provided the Slavic speaking peoples a written language called Cyrillic, after the monk Cyril who helped create it. Russia and Eastern Europe also adapted art and literature from the Byzantines, as well as architecture.  In return, these areas became important trading partners for the Byzantines. 

Byzantine Empire