Simplify the following text for a Grade 18 native English-speaking person.
Original: The term can also be used for the art of Eastern Orthodox states which were contemporary with the Byzantine Empire and were culturally influenced by it , without actually being part of it ( the `` Byzantine commonwealth '' ) , such as Bulgaria , Serbia , or Rus and also for the art of the Republic of Venice and Kingdom of Sicily , which had close ties to the Byzantine Empire despite being in other respects part of western European culture .
Simplified: But the term can also be used for the art of states at the same time as the Byzantine Empire which had a common culture with it , such as Bulgaria , Serbia , or Rus ; and also for the art of the Republic of Venice and Kingdom of Sicily , which had close ties to the Byzantine Empire though they were part of western European culture as well .