During the middle ages, there are frequent reports of the occurrence of extraordinary or supernatural phenomena was around Masakado-zuka (the burial mound of TAIRA no Masakado); in order to quiet the fears of the people of that time, who feared that such phenomena were due to the wrath of Masakado's spirit, the yugyo-so monk, Shinkyo of Jishu enshrined Masakado as a god, and in 1309 he was recognized as a god at Kanda Myojin.
中世、将門塚（平将門を葬った墳墓）の周辺で天変地異が頻繁に起こることがあり、これを将門の祟りと恐れた当時の民衆を静めるため、時宗の遊行僧・真教によって神と祀られ、延慶(日本)2年（1309年）には神田明神に合祀されることとなった。