Abbasid Caliphate overthrew the Umayyad Caliphate and ruled from 750- 1258; descendants of the prophet Muhammad's uncle, al-Abbas bubonic plague disease spread by fleas bites to rodents and humans; high mortality rate and difficult to prevent spread Byzantine Empire Eastern Roman Empire caliphate office established in succession to the prophet Muhammad to rule the Islamic empire Champa rice quick-maturing rice that can allow two harvests in one growing season; brought to China from Vietnam Charlemagne King of the Franks; established the Carolingian Empire; first to hold the title of emperor in Europe in over three hundred years Crusades series of religiously inspired Christian military campaigns against Muslims in the eastern Mediterranean that