Land taken by Nordics.

[Cristiano viejo]

I kinda like that part around the Bay of Biscay. And they tried hard indeed.

Well, in fact the map is so nonsensical that hurts... but remember that Visigoths founded the city of Vitoria, for example.

[Gwydion]

I like dem Gaels in OPs pic though: can't get conquered when instead of 1 king you have 100s of kings with all of their own underkings constantly at war with each other and thereby keeping the Indo-European heroic age ideals alive into the Middle Ages and beyond.

Also one has to consider the Ui Imair dynasty and the Vikings in Scotland, Ireland, and Mann were strongly mixed and sometimes largely Gaelic by blood, especially the further you moved south from Orkney/Caithness/the Outer Hebrides.

[PaleoEuropean]

Rome bowing before the Ubermensh Goths

[Gwydion]

Rome bowing before the Ubermensh Goths

Armor looks more like La Tene Celts.

Some Germanic peoples and most Celtic peoples (excluding Caledonians who Rome did indeed try and fail to conquer) were conquered by Rome, but which of their neighbors weren't? The entire Mediterranean world fell to the Romans, who by the way in terms of linguistic origin and partly Y-DNA origin were Italic people closely related to the Alpine Celts and thus at least in origin and by language more closely connected to the Celts than to many of their other neighbors.

Also let's consider that all ancient powers failed to conquer the city of Rome excluding the Celts who sacked it 390 BC and later the Goths, so in both cases the Celto-Germans beyond the Alps.

Rome's worst defeat by casualties was likely Arausio at the hands of the Cimbri, despite the latter losing the war.

And in the end Rome failed to conquer Germania but the Germanic tribes carved out the Roman Empire among themselves. Western Rome's fall of course has a multitude of factors involved but Germanic invasions are among those factors.