Ten'an (天安) was a Japanese era name (年号,, nengō,, lit. "year name") after Saikō and before Jōgan. This period started in February 857 and ended in April 859. During this time, the emperors were Montoku-tennō (文徳天皇) and Seiwa-tennō (清和天皇).
Ten'an (天安) was a Japanese era name (年号,, nengō,, lit. "year name") after Saikō and before Jōgan. This period started in February 857 and ended in April 859. During this time, the emperors were Montoku-tennō (文徳天皇) and Seiwa-tennō (清和天皇).