During his reign the Mongolians invaded Japan (Genko, Mongolian Expeditions against Japan) twice, the Emperor acted eagerly to pray at Ise Jingu Shrine, etc. (During this period, both the Retired Emperor Kameyama and Emperor Gouda, father and son, prayed at Ise Jingu Shrine and were ready to sacrifice themselves to help the nation, however it is not clear who to appreciate for this, the Retired Emperor Kameyama or Emperor Gouda, and this was a big controversial theory between the scholars during the Taisho period and the issue still has not been concluded.)
院政中には2回の元の対日侵攻（元寇）が起こり、自ら伊勢神宮で祈願するなど積極的な活動を行った（当時の治天・亀山上皇と天子・後宇多天皇の父子いずれかが「身を以って国難に代える祈願」を伊勢大神宮に奉ったことは史実のようだが、さて父子のどちらにその祈願を帰すべきかは、大正年間に学者の間で大論争を呼んでいまだ決着のつかない問題である）。