1649
Since the Anglo-Saxons took over the region in the 8th century , it has stretched between the River Monnow and River Wye , but it derives from the once much larger Welsh kingdom of Ergyng .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 None