I personally think, it´s not so easy to declare a germania territory, because the germanic tribes never see themselve as a nation with a territory.

the german word "Volk" for citizens/inhabitants is the best example. it meens "to follow". So in later times every one could be a german, as long as he follow the band.
Blood was not importent, like the battle at the "katalaunischen feldern"(don´t know in english, also not in eb timelimit)

attila vs roman empire =
austrogoti(eastgoths) vs wisigothae (westgoths)

but i find some sources that could help you in a good lexika:




source "die germanen" hannsferdinand döbler isbn 3-572-01157-4