(According to "Fuso-Ryakki", he died from an illness, but another explanation that has been offered is that he went missing in the mountains and that Emperor Temmu had him assassinated.)
（『扶桑略記』では病死説の後一説として「一云天皇駕馬幸山階鄕更無還御永交山林不知崩所只以履沓落處爲其山陵以往諸皇不知因果恒事殺害」とあり山中で行方不明になったとされることから天武天皇側による暗殺説もある）