The secret of Birkenstock's enduring success - Pandemic restrictions have meant one thing for most wardrobes: comfort. As many of us continue to work from home -- and staying safe with a trip to the park remains the height of summer's social calendar -- sensitive flat sandals are now more pervasive than ever.

And, it seems, the ultimate expression of this phenomenon is a pair of Birkenstocks.

Last month British Vogue declared Birkenstocks the official sandal of 2020, while fashion search engine Lyst reported that they had become the platform's most searched-for shoe. Meanwhile models Kendall Jenner, Gigi Hadid and Kaia Gerber have all stepped out in theirs -- with and without socks. Not bad for a shoe that claims to have always put its orthopedic prowess above its fashion appeal.Before Ugg, Crocs, Hasbeens and Fitflop, there was Birkenstock. With its tagline "often copied, never equaled," the storied brand's lineage goes back over two centuries. Now, in these times of uncertainty, there is something reassuringly reliable about this durable sandal.

With its boat-like natural cork, jute and latex sole and chunky buckled straps, Birkenstocks make an anti-fashion statement that transcends trends -- yet somehow keeps managing to set them.

Origins of comfort - The earliest records of the family shoe business date back to Johann Adam Birkenstock, who worked as a cobbler in Langen-Bergheim, Germany in 1774. By 1896 his grandson, Frankfurt-based shoemaker Konrad, had opened two stores and launched the fussbett (footbed), anatomically shaped insoles that support and form to your foot. By 1925 they were being sold across Europe.

The company expanded into week-long educational courses for medical professionals on the musculoskeletal and circulation benefits of its specialist footwear. Then in 1947 Konrad's son Carl published the book "Podiatry -- The Carl Birkenstock System," expounding his approach to supporting one's "natural gait" to achieve healthy feet. This was the first of several Birkenstock textbooks and manuals filled with bracing ideas -- such as walking barefoot in nature and soaking feet in spruce needle salts and cold water.

The 1960s proved to be the making of Birkenstock as we know it today. In 1963 Carl's son Karl launched the first sandal, the single-strap Madrid, initially marketed as a gymnastics shoe and still a key style today. Three years later, Margot Fraser, a German dressmaker living in California, was holidaying back home -- drawn as many were to the country's no-nonsense sanatoriums (austere precursors to the modern spa) -- and was recommended a pair of Madrids as therapy for her aching feet.Immediately smitten, she approached the family to become the brand's first US distributor. Fraser initially struggled to drum up interest from shoe sellers, and ended up finding a spot for the sandals at health food stores instead.

Here hippies discovered them snuggled next to vitamins and dried lentils, and as the Summer of Love unfolded, Birkenstocks became the shoe of choice for beatniks from San Francisco to Vermont. This new-found cool didn't stop the brand's catalogs from promoting the shoes to everyone -- housewives, golfers, doctors and chefs come all.

The two-strap Arizona sandal arrived in 1973, which became -- and remains -- the brand's bestselling style.

Counterculture couture

Over the years many subcultures have embraced Birkenstocks as part of a uniform, from surfers and skaters to Deadheads, but it took until 1990 for high fashion to fully take notice. The trend (like many from that decade) originated with Kate Moss. The teenager posed for photographer Corinne Day's July cover shoot for The Face magazine wearing Birkenstocks on the beach. This youthquake moment led to Marc Jacobs choosing the sandal for his Spring-Summer 1993 grunge collection show for Perry Ellis, and soon the shoe was duly adopted by college students and musicians to complement their plaid shirts and baby doll dresses.

A decade later Birkenstock saw another spike in status thanks to West London A-listers including Jude Law and Jade Jagger, then Gwyneth Paltrow, who made headlines for preceding heels in favor of these flats during her time in Britain's capital in 2002.Two years later Heidi Klum launched her own limited-edition sandals, featuring biker studded leather and distressed denim. (In tandem with these celebrity endorsements, the noughties were also a time when the pejorative term "Birkenstock liberal" was used by conservatives to invoke the stereotype of a granola-eating, Volvo-driving do-gooder.)