Assertion: empire's emperor | /r/CapableOf | make significant gains
Facets:
Source sentences:
text: In 687–688, the final Heraclian emperor, Justinian II, led an expedition against the Slavs and Bulgarians, and made significant gains, although the fact that he had to fight his way from Thrace to Macedonia demonstrates the degree to which Byzantine power in the north Balkans had declined.