When Fereydoun Najafi Aria was 18, he heard a knock at the door, and his first instinct was to protect his family.

"I said to my brother: 'Go hide'," he says.

Mr Najafi Aria had no idea that within moments, he'd be arrested and sent to prison, where he would spend the next 10 years.

It was 1981, and in the aftermath of the revolution that saw Iranian monarch Shah Mohammad Reza Pahlavi toppled in favour of an Islamic head of state, thousands of anti-government protesters were being arrested.

The ripples of the Iranian revolution are still being felt. ( Getty: Michel Setboun )

The men at the door were Revolutionary Guards.

"The guy just pushed me aside and started to search everywhere," Mr Najafi Aria says.

The guards didn't find the two-metre-wide printer — used by his family to produce anti-government flyers, pamphlets and posters — hidden in the ceiling.

But they found Mr Najafi Aria's brother. The pair were taken to Tehran's Evin jail: a prison at the foot of the Alborz mountains, notorious for housing political prisoners.

There, he says he was tortured.

"After that night, I couldn't move for 40 days."

'They killed all my friends'

This week marks 40 years since the 1979 revolution and the establishment of an Islamic republic.

Some Iranians have celebrated the anniversary in Tehran's Azadi Square, holding cut-outs of Ayatollah Khomeini or waving Iran's colours — red, white and green — against a drizzled winter sky.

Some Iranians marked the anniversary of the Iranian revolution by celebrating in Azadi Square in Tehran. ( Getty: Atta Kenare/ AFP )

But for some, like Mr Najafi Aria, who eventually resettled in Australia as a refugee, the anniversary isn't necessary an occasion for celebration — it's about reflection.

"I [didn't] believe revolution is the way, even before [the] revolution."

Looking back, Mr Najafi Aria says he's fortunate, as a political prisoner, to have survived.

"They killed all my friends," he says.

In Australia, Mr Najafi Aria has been able to pursue a deeply-held passion: writing.

"When I was a kid, I was writing short stories. When they arrested us, they took all of [my papers]," he says.

"This is my dream… [to] come to somewhere like Australia to write."

Mr Najafi Aria works in painting and decorating in Sydney, but says writing is his true passion. ( ABC RN: Siobhan Hegarty )

'I gave my life to them'

His younger sister, Katauon Najafi, wasn't at home when her brothers were arrested.

She returned home to find her cousin hiding behind a car outside.

"She just said: 'come here'. Quickly I changed my jacket, and just [ran]," she says.

Then Ms Najafi went into hiding.

Katauon Najafi says Australia is her "second home", but she's still living with her past memories. ( ABC RN: Siobhan Hegarty )

While Ms Najafi had initially supported the Islamic revolution, by then she was involved with the People's Mujahedin of Iran, a political-militant organisation.

Mahmoud Pargoo, a doctoral candidate with the Australian Catholic University researching post-revolutionary Iran, says the mujahedin were supported by left-leaning activists.

"In 1979 and 1980, they were popular," he says.

"But later, when they changed their position and made an alliance with Saddam Hussein in the war against Iran, it was very disappointing for people and [the mujahedin] lost the support."

Years later, living under a different name and married with two young children, Ms Najafi joined the mujahedin in Iraq.

She says her now ex-husband pressured her to rejoin their forces.

"I didn't want to go. I pushed myself. My ex didn't give me a chance to say no," she says.

"They say, 'your brother is in jail, your friends die ... how could you live with this?'"

At Camp Ashraf, Ms Najafi lived in quarters with other female fighters.

From 7:00am to 7:00pm, she says, "the kids were in childcare" and she was learning how to use weapons.

"They said one week ... but I stayed a few years."

Kataoun Najafi spent four years in Iraq with the mujahedin. ( Supplied: Katauon Najafi )

Now, Ms Najafi languishes the lost years she devoted to a cause she now firmly doesn't believe in.

"I'm embarrassed to say I was mujahedin," she says.

"I gave my life to them. I was 20 when I went there. I lost my country … I can't even go to Iran."

She also settled in Australia as a refugee, and had an "amazing" reunion with her brother.

"We have a life here. This is my second home," she says.

The brother Mr Najafi Aria told to hide four decades ago is now in the US, and has two children.

A new generation

Sixty-three per cent of Iranians were born after the 1979 revolution, but according to Charles Sturt University Associate Professor Mehmet Ozalp, they are no more religious than those who lived in the country before it became an Islamic republic.

"[Those born after 1979] have no experience of a Shah era, they were educated by the current government and its instruments, schools, so they should be influenced — they should be shaped by the revolution and the society its created," he says.

"Despite that, and the push for religion, people are not religious.

"People want freedom and they respond negatively when religion is pushed down from governmental means."

Acting student Shayan Askari, 28, is part of that 63 per cent.

Born in Tehran, he attended strict Islamic schools and, as a teenager, became "almost fanatic" in his religious beliefs.

"In that secluded environment, far away from the society ... I slowly became very influenced by the religious teachings," Mr Askari recalls.

"I wasn't doing anything to harm other people and I wasn't taking on the political agenda, but I was into the religion itself and was like, 'This is the key to finding happiness and truth'."

Shayan Askari says Iranians need to call out injustices, instead of being "silent observers". ( ABC RN: Farz Edraki )

Mr Askari's parents, who he describes as "culturally religious", soon became worried about his son's uncompromising beliefs.

"I didn't want to say my prayers inside their house because I was like, 'You haven't paid the one-fifth of your liquid assets to the poor,'" Mr Askari recalls, referencing the Islamic tenet known as 'khums'.

"I was mad at my parents and [thought] my prayers will not be accepted — I'm going to the mosque at 4:00am to pray."

But Mr Askari's religious fervour didn't last.

At 17 — just one year before he was due to be conscripted for two years of military service — his parents sent him overseas to study.

"The plot twist happened when I went to Malaysia and had access to uncensored internet," Mr Askari says.

"That was around the time where the election was happening in Iran with Ahmadinejad 'elected' — really chosen — to be the president of Iran and lots of riots were happening."

Spurred on by fellow Iranian students, Mr Askari began digging into his homeland's past — learning, for the first time, about the revolution and its violent aftermath.

"I was like, 'Oh my God, the killings, the imprisonment'," he says.

"It hit me really hard — that was all just means for the regime to control. Around that time, I stopped practising the religion."

Shayan Askari's family are all still in Iran. ( Supplied: Shayan Askari )

Freedom, without fear

In 2009, Mr Askari moved to Australia on a student visa to study business, but now he's following his true passion: acting.

He says many actors in Iran face a real risk of arrest and imprisonment if their performances are deemed 'immodest'.

"I'm part of this show, A Midsummer Night's Dream, coming up in two weeks [in Sydney]," Mr Askari says.

"A few months ago, actors were put into prison for doing the same show in Iran. They had this bit where they did a bit of dance on stage and I guess they didn't pay the right person to zip it up."

Like Mr Najafi Aria, Mr Askari is part of Sydney's Persian community theatre group.

"There are lots of good theatres in Tehran, so I was like, 'I'm going to go learn [acting] from Iranians now' and that's where I met Fereydoun," he says.

"I've gotten to be more in touch with the repercussions of what Islamic Republic has done to Iran."

Mr Najafi Aria enjoys working with younger Iranian-Australians, like Mr Askari, and is hopeful about Iran's younger generation.

"At the moment, we have a good new generation and they are very smart, they are very intelligent," he says.

"So I see the future is very clean and right."