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From the 6th century into the 7th century , the Slavs crossed the Danube and largely absorbed the indigenous Ancient Greeks , Illyrians and Thracians in the Balkans ; thus , the Illyrians were mentioned for the last time in historical records in the 7th century .
 Danube, Balkans
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Danube, Balkans