As soon as I saw a picture of Mahmoud Ahmadinejad, Iran's new president, I knew there was something faintly familiar about him.
Mahmoud Ahmadinejad is the first non-cleric to become president
And it was not because he was mayor of Tehran, because, like many other Western journalists, I have been barred from visiting Iran in recent years.
But in the years soon after Iran's Islamic Revolution, I met him and interviewed him.
He was the kind of person you don't forget - intense, articulate, and very fierce in his opinions.
Looking back 20 years, it seemed to me I must have met him at the former US embassy, which had been taken over by revolutionary students some years earlier; but after two decades precise memories fade, and I can't be absolutely certain.
Unfortunately the television rushes, which would have made it all clear, haven't been kept in the BBC archives.
Several former hostages from the embassy are certain that the new president is the man who captured them.
A photograph taken by an Associated Press cameraman of a revolutionary escorting a hooded American prisoner looks rather like President Ahmadinejad, but men with beards and deep-set eyes were not exactly in short supply in Tehran at the time.
The president himself insists it wasn't him, and several of the leading revolutionaries who were in the embassy at the time say he wasn't there with them.
Since these men are now his strong political opponents, that seems pretty conclusive.
But in Washington, the Bush administration has seized on the possibility that President Ahmadinejad was indeed part of the group which took over the embassy and humiliated the United States for 444 days.
This will undoubtedly affect Washington's future relationship with Iran.
Times change, and so do international politics.
Back in the 1980s, virtually every supporter of the Iranian revolution would have supported the take-over of the embassy.
But it is acutely embarrassing for Mr Ahmadinejad now to be associated, mistakenly or not, with the group which swarmed over the embassy wall in 1979.
He is the first non-cleric to hold the presidency since Ayatollah Khomeini died in 1989, yet he is much more fundamentalist than either of the religious figures who have been in office since then.
He was just about the only person inside or outside Iran who wasn't surprised by the result of the election.
Except, perhaps, for the Americans.
They assumed anyway that Iran was a country seething with hatred for the US and determined to dominate the region by threat and undercover terrorism.
The British, French and Germans were the most taken aback, because they had previously argued that the Iranian government was basically pretty moderate and wanted to reach an accommodation with the West.
So far, Mr Ahmadinejad has done his best to stress his moderation; hence his government's anger at any suggestion that he might have been involved in taking over the US embassy.
Yet there is no doubting his basic commitment to Ayatollah Khomeini's revolution.
Politics is far more fractured in Iran than in most Western countries, and expressions like "the conservatives" or "the reformists" have much less practical meaning in the Iranian Majlis than they would in Congress, the Commons, the Reichstag or the Chambre des Deputes.
In the Majlis, Mr Ahmadinejad has had the support of a group - as in other post-revolutionary societies, Iranian politicians still instinctively steer away from the concept of outright political parties - known as the Abadgaran, or "the developers".
Many Abadgaran members are like him: under 50, often from working-class backgrounds, intense, strong believers still in Ayatollah Khomeini's revolution of 1978-79.
Iranian politics are as complex and sophisticated as any I have observed around the world
They even dress alike, with their dark suits, their beards, their open-necked shirts.
The differences with the establishment figures who support Ayatollah Khamenei are considerable.
There is nothing working-class about them, and (unless I am reading it very wrong) Mr Ahmadinejad's huge success in getting out the vote in the slums of south Tehran and elsewhere will have unsettled them.
The Khomeini revolution, back in 1978 and 1979, claimed to be acting in the interests of the poor against the wealthy and corrupt.
Still, though, the class divisions in Iran are as strong as ever. Few poor people have made it to the top in Iran - until now, that is.
Iranian politics are as complex and sophisticated as any I have observed around the world.
The complexity is increased by Iran's constitution, which gives the unelected religious leadership greater powers than those of the elected president.
This was why President Khatami, who wanted to open the country more to the West, never could. The gridlock always stopped him.
President Ahmadinejad will certainly move in the opposite direction. He has already reversed many of Khatami's earlier changes in Tehran.
If his followers harass people, attacking men who shave and women who show their hair, wear make-up and bright colours, there will be much greater social tension and the possibility of future violence.
The implications of this will be worrying to the religious leadership. It is the better-off in Iran who usually want to follow Western styles.
And although Ayatollah Khamenei is a religious conservative, he will not want class warfare breaking out in the streets.
So although President Ahmadinejad won a sizeable majority last Friday, he will not necessarily be able to do what he wants.
US embassy workers were held hostage for more than a year
Ayatollah Khamenei, who intervened before the election to ensure that leading reformist presidential candidates who had been forbidden to stand were put on the ballot-paper after all, sees himself as a referee in Iran's political life, not just another political player.
But Mr Ahmadinejad and Ayatollah Khamenei will certainly agree about one thing - the nuclear issue.
Iran believes it lives in a difficult neighbourhood, with Israel, China, Russia, India and Pakistan close by - all nuclear powers, real or potential - and the US over the horizon.
Iran wants the nuclear option too.
The US is no overwhelming threat to Iran now, unless it decides to attack it from the air and alienate world opinion utterly.
The best the British, French and Germans can do is persuade Iran to be more cautious and tactful in following its nuclear ambitions. Ayatollah Khamenei may see the sense of that.
But unless I have remembered him wrongly from the old days, caution and tact are not qualities you immediately associate with President Ahmadinejad.
Ahmadinejad's election seems very typical of political process anywhere in the world - picking the lesser of the evils. His past ties are of concern, in the stances he takes within Iran, or how he interacts on the international platform. "Peaceful" nuclear pursuit is a cover for the real intention of developing nuclear arms.
David, Washington, DC, USA
I think it's strange that a Iran had a truly democratic election and the US is still not happy. So what if he is a conservative, that is apparently what the people want. Need I remind people that when Bush won the US elections there was a global outcry because he is a serious conservative (as a liberal I was one of those people crying). If anything, it is Bush that as proven himself to be a hot-headed extremist by charging off to war without forethought or plans. People voted for Ahmadinejad knowing his nuclear ambitions and his attitude towards the West. He is what a majority of the people wanted, that is the definition of democracy.
Simone Brown, Scottsdale, Arizona
Being in Iran I think Ahmadinejad won the election freely the people (poor uneducated) truly did vote for him but the choice in Iran is not between democratic candidates it is between the evil and the horrible. Iran chose the horrible.
Reza, Isfahan, Iran
He is, in fact, no different than any other person seeking a political position, they all have something in their background that they choose to hide. Only time will tell us what type of leader this man will be.
Lissa, Vienna, USA
I didn't vote in the recent elections because elections in Iran are almost never real. I only ever took part in two elections, one was the vote for an Islamic republic and I have never forgiven myself for voting yes. Nobody had told us about mullahs and what type of human beings they are.
Mehdi, London, UK
I am not the guy who loves Iran's extremism or USA's ridiculous policies. But i respect the choice of the people. Ahmadinejad is the Iran's elected president, like Bush in the US (while some people hate it). We should respect the choice of people and welcome them.
G.M.Hasan, OK, USA
If Mr Simpson, or anyone else, has actual credible evidence that Dr Ahmadinejad was one of the hostage-takers, then let them show it, for the sake of historical record, not political vengeance or crass financial gain, as in the case of the former hostages and their lawyers.
Mojtaba Aghamohammadi (Moji Agha), Tucson, Arizona, U.S.A.
Nuclear capability in the hands of irrational leaders is unacceptable, despite the intentions stated. Had Iran worked to improve its relationships with the West over the last 10 years and especially since 9/11, I would be much more accepting of their intentions. If Iran really wants peaceful nuclear capability without objection from the West, perhaps they should dismantle the terror organisations within the country, as an act of good faith.
Brad, O Fallon, Missouri, US