FUJIWARA no Yukinari who attended deathbed of the Retired Emperor Ichijo testifies that Keien was served as kaishi (a priest who imparts the Buddhist commandments) in 1011 when the Retired Emperor Ichijo entered into priesthood just before his death and Keien's incantation temporarily revived the Retired Emperor at the last minute of his life ("Gonki").
寛弘8年（1011年）に一条上皇が崩御直前に出家した際の戒師を務め、崩御の直前慶円の加持によって一時的に蘇生したことが上皇の崩御を看取った藤原行成が証言している（『権記』）。