Minamoto no Hikaru (源光)
MINAMOTO no Hikaru
Regarding a court noble in the Heian period, MINAMOTO no Hikaru (a prince of Emperor Nimyo, udaijin [minister of the right]), refer to MINAMOTO no Hikaru (court noble).
As for a Buddhist monk in the Heian period, Genko (the Chinese characters are the same as MINAMOTONO Hikaru; a monk who lived in Mt. Hiei under whom Honen studied), refer to Genko (Buddhist monk).
In addition, the main character of "Genji Monogatari" (The Tale of Genji), HIKARU Genji is different from the name MINAMOTO no Hikaru. "Hikaru (a shining prince)" is not a posthumous name but a nickname.