Did the Vlachs or Romanians do anything of significance between 400-1300 A.D.?

The origins of the Vlachs and Romanians are uncertain/controversial, but historically did they do anything of significance between 400-1300 A.D.? I hear mentioning of them playing an important part in the Bulgarian empire, but to what extent? Did they work as soldiers or settlers? They were ruled by various peoples, from the Huns to the Mongols and Wallachia/Moldova are mentioned as semi-independent states by the 1300's.


I didn't find the right solution from the internet.
References:
http://histor um.com/european-history/127697-did-vlachs-romanians-do-anything-significance-between-400-1300-d.html
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