You may never have heard of Don and Doris Fisher, but it's a reasonable bet that at some point or another you have worn their clothes.

Mr Fisher, who died at the weekend in San Francisco at the age of 81, was, with his wife, the founder of an astonishingly ubiquitous chain of clothing shops with a certain three-letter name.

This would be the Gap, a retail brand that was to become almost a cultural touchstone of risk-free urban cool around the world.

It made it not just acceptable but almost de rigeur for men to own at least two of the following items: crisp white T-shirts, ironed khaki trousers and not-so-ripped (but hopefully not ironed) denims.

It even helped to spawn that most subversive of workplace revolutions - dress-down Fridays.

And if it was embroiled in more than one row over its labour practices, it also worked hard to build a reputation as a firm with ethics to match its squeaky-clean aesthetic.

The death of Mr Fisher, who will also be remembered, in California especially, as a hugely generous philanthropist and a prodigious collector of modern art, is also a reminder of something else that may surprise many: last month saw the 40th anniversary of the opening of the first of his Gap shop.

Yes, Gap shoppers, or some of us at least, are not so young any more.

How it all started has long been a part of San Franciscan and retail legend.

It was the summer of 1969 - the time of joyous rebellion, pot-smoking and the Beatles - when Mr Fisher, a property developer just the wrong side of 40, was trying in vain to exchange a new pair of jeans that did not fit. In their frustration, he and Doris decided to open a shop of their own with a keener eye on choice and service.

Mrs Fisher was the one who first floated the notion of naming the shop in honour of the famous "Generation Gap" that separated the post-war baby boomers from their parents. That was a bit long, and so the shop, on Ocean Avenue, was launched on 21 August 1969 under the simple name, Gap.

A highly successful athlete and avid sports fan, Mr Fisher staffed the shop in part with local football players.

He was later to become one of a group of San Francisco business tycoons who bought the city's Giants baseball team to keep it in town when it was about to be bought and moved to Florida.

Over the next 50 years, that single Gap outlet grew into a retail empire spanning many continents.

Today, the company and its subsidiaries run more than 3,000 shops in 25 countries, and these turned over more than $14bn (NZ$31bn) last year.

"I didn't plan to go into the clothing business. I was just fortunate to have a bit of bad luck," Mr Fisher said with ample understatement two years ago, in an article for the campus magazine of the University of California at Berkeley, where he was once a student.

"Today we lost a friend, a mentor and a great visionary," Gap's chief executive and board chairman, Glenn Murphy, said on Sunday.

"Don and Doris took a simple idea and turned it into a brand recognised as a cultural icon throughout the world and changed the face of retail forever."

Mr Fisher held the chief executive's post himself until 1995, when he stepped back to become chairman, and later a director and chairman emeritus.

In a memo sent to branch managers earlier this year, Mr Fisher said: "I look at running a store and running a business as playing a game. And what do you do when you want to play a game? You want to win."

There have, of course, been times when Gap's pursuit of success has led it into trouble.

In 2003, sweatshop workers in Saipan named it in a class action over unpaid overtime and poor working conditions, a deal the company settled without admitting liability; and while it has since strived to improve its working practices, a 2007 investigation found that an item sold in Gap stores was made using child labour.

But - perhaps mindful of good PR as much as ethics - the company has since redoubled its efforts to stamp out such practices amongst its suppliers.

Mr Fisher died just two days after signing an agreement with the San Francisco Museum of Modern Art, under which it will construct a new wing to house the roughly 1,100 pieces of 20th and 21st-century art that Mr Fisher had in his collection.

Earlier this year, he abandoned plans to build a museum of his own in the Presidio district of the city in the face of opposition from residents.

Meanwhile, tributes were paid yesterday to Mr Fisher for his long-standing work as a philanthropist.

A conservative Republican who backed the Bush family with large donations, as well as Arnold Schwarzenegger, the Governor of California, he also invested $100m in a range of education causes. Most notably, he was a supporter of the Knowledge is Power Programme, KIPP, which operates 80 privately funded schools to help underprivileged students go to university.

"He treated people with respect and worked to make a significant impact in his community, making it a better place for people to live, grow and prosper," Mr Schwarzenegger said.

The Mayor of San Francisco, Gavin Newsom, added: "His unwavering commitment to our city's arts and civic culture will be remembered for generations to come."

That memory will undoubtedly remain. But if some of us who have shopped at Gap over the years have begun to show signs of ageing, so too has the chain.

It has struggled in recent years in part because it may have expanded too fast.

And pretending you are still fresh and frisky by dressing up in jeans, T-shirts and khakis may at some point cease to work as well as it did in the past.

- INDEPENDENT