284547
Drawing on a variety of sources , his history deals with events in the Byzantine Empire , Egypt , as well as Bulgaria and the Kievan Rus ' .
 Byzantine Empire, Egypt, Kievan Rus '
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Byzantine Empire, Egypt, Kievan Rus '