Conversation so far:
Where did Ruhollah Khomeini live before returning to Iran?
Ruhollah Khomeini spent more than 14 years in exile, mostly in the holy Iraqi city of Najaf.
What year did Ruhollah Khomeini return to Iran after exile?
On Thursday, 1 February 1979, Ruhollah Khomeini returned in triumph to Iran.
Why did Ruhollah Khomeini decide to return Iran after exile?
Ruhollah Khomeini decided to return to Iran after Mohammad Reza Pahlavi, the Shah of Iran, fled on 16 January 1979.

Question: Why was his exile lifted?
Self-contained rewrite: Why was Ruhollah Khomeini's exile lifted?