I only want to point, that:
- Slavic scientists usually use words like ,,peacefull assimilated" instead of ,,conquered" :) Just like Balts do the same when speaking about Ugrofinns
- There is some wild theory that Slavs are those Balts, who left their homeland and where conquered by Huns etc. I've read that once in one, single article.
- Note about Slavs pledging allegiance to Emperor is irrevelant, since only small group of Slavs, (only from Western branch) did that, while expansion was done mainly by Eastern branch. I would suggest removing that sentence or putting more about other political entities which tried to overrun Slavic tribes plus info about states Slvs do.
- anyway HRE is anachronic, since the term started to be used in, IIRC some XIII century. .