After the fall of the Roman Empire, the area was invaded by Bavarians, Slavs and Avars. Charlemagne, King of the Franks, conquered the area in AD 788, encouraged colonization, and introduced Christianity. As part of Eastern Francia, the core areas that now encompass Austria were bequeathed to the house of Babenberg. The area was known as the ''marchia Orientalis'' and was given to Leopold of Babenberg in 976.