[...]Is this where the term Indo-European languages come from?
Indo-European are Celtic, Latin, Germanic, Slavic, Greek, Indian, proto-Iranian etc... and they all descend from the "proto-Indo-European" language from the Bronze Age. Their speakers share alot of similarities: polytheism (many gods in their mythologies) for example, which is unlike the Semitic/Hebrew group who worshipped one god exclusively.
But I digress
I'm gonna order tickets to see Ensiferum, Enslaved and Katatonia (with Alcest opening)!!
EDIT: one of the pics I saw on Wikipedia. It says alot more than what I could