The actors depicting the German tribes people in the series speak in German (albeit Modern German) but this series is notable as one of the only historical dramas of its kind in which dialogue for the Roman characters is all spoken in classical Latin.
The helmet with a mask worn by Ariminus in the episode "Wolf & Eagle" is an exact model of the Roman cavalry helmet found in excavations in Kalkriese (site of the last battle of the Varus disaster).
The character of Folkwin Wolfspear in completely fictional unlike Arminus and Thusnelda who truly existed.