Epopee is an older term for an epic poem, especially a long narrative poem that tells a serious story of heroic deeds, legendary events, or the fate of a people. It may also be used more broadly for an epic-style work or a grand narrative treated in an elevated way.
Example
Across storm and empire, the king sailed home
with shattered shields, a vow, and a lost son;
the hills remembered every step he took,
as if the road itself were singing back.