User blog comment:D. Cello/Assassinews 03/05 -- ACWiki's Fan Section and AC3 first trailer/@comment-4829046-20120307062922/@comment-213.143.108.116-20120308160022

Sounds a little bit like it was inspired by the Celts. They also used their "barbaric" singing and war horns to frighten their enemies and egging themselves on.