In my studies at the Citadel, I've found the Great Schism between the Faith of the Seven and the Old Gods to be most fascinating. The Andal invasion brought the Seven across the Narrow Sea, fundamentally changing the religious landscape of Westeros.

While the South embraced the Seven's structured doctrine and septries, the North held firm to their ancient heart trees and nameless gods. This divide runs deeper than mere belief - it represents two distinct cultural identities that persist to this day.