Because it is clear that Ichiniwa Tumulus which had existed since before the construction of Heijo-kyo (the ancient capital of Japan in current Nara) is not a tomb mound made for Emperor Heizei who was a person in the Heian period, there are many negative opinions on the authorization of the imperial mausolea.
平城京の建設以前から存在した市庭古墳が、平安時代の人物である平城天皇のために造られた古墳でないことは明らかで陵墓の治定に否定的な意見が多い。