Original: Among these early groups, the Irish band Cruachan and the German band Subway to Sally each spearheaded a different regional variation that over time became known as Celtic metal and medieval metal respectively.
Simplified: The Irish band Cruachan was one of these early bands, and so were the bands Orphaned Land, from Israel, and the German band Subway to Sally. Each band started to develop their own styles of folk metal and these styles became Celtic metal, Oriental metal and Medieval metal.