Watch part two
On February 1, 1979, Ayatollah Ruholla Khomeini returned from exile to Tehran, where he was greeted by millions of Iranians at the airport.
Days earlier the last Shah of Iran, Mohammad Reza Pahlavi, had fled the country, a year after public demonstrations had begun against his rule.
"There was a paradox at the heart of the man," says Abbas Milani, the biographer of the Shah.
When Pahlavi fled Iran on January 16, 1979, never to return, it was an inglorious end for a man who was both a moderniser and an autocrat.
To his supporters he was a patriot, to his critics a Western puppet.
Rageh Omaar talks to those who knew him to find out who the self-proclaimed king of kings really was.
I knew the Shah can be seen from Monday, October 12, 2009 at the following times GMT: Monday: 0530, 1130; Tuesday: 0130,1400, 2330; Wednesday: 0630, 1630; Thursday: 0300, 1430; Friday: 0600; Saturday: 1930; Sunday: 1030.