>>718115441
Two major wars of secession in 1000 years is a pretty good record for rewriting history in an attempt to maintain a lasting peace. Rhea isn't perfect but she did the best she could, especially while still grieving her mother (which would also continue for 1000 years.)
Elsewhere in Fire Emblem, rewriting history wouldn't keep wars from happening basically at all and that covenant would come undone in ~640 years.