For the span of recorded history starting roughly 5,000-5,500 years ago, see Ancient history.
Ancient are a band that, while not really troll metal, had troll metal themes on their EP 'Trolltaar'. They used to have a raw black metal sound, similar to Darkthrone's blacker works. Then, beginning with The Canaan Chronicle, they moved towards a more Nordic/atmospheric blackmetal sound, like Emperor. They went on to add Gothic-style instruments like violins, female vocals and synthesizers to their music, then moved to the United States and became obsessed with vampirism.