Conversation so far:
How long was Nikolai Yezhov in power before the fall from power?
Yezhov became People's Commissar for Internal Affairs and a member of the Central Committee on 26 September 1936. Yezhov was appointed People's Commissar for Water Transport on 6 April 1938.
where was Nikolai Yezhov in power?
Nikolai Yezhov became People's Commissar for Internal Affairs (head of the Soviet Union's interior ministry) and a member of the Central Committee on 26 September 1936.

Question: how old was he when he fell from power?
Self-contained rewrite: how old was he when he fell from power?