President Obama caused a flap early this year when he became the first U.S. president ever photographed in flip-flops—he was on vacation in Hawaii. This threw fuel on the footwear flame war of the decade: When is it acceptable to wear flip-flops? Fashion experts Clinton Kelly, Stacy London, and Tim Gunn have expressed disdain for the cheap, rubber thong sandal that’s made its way into office casual attire. We asked author and shoe expert Elizabeth Semmelhack, the Senior Curator at the Bata Shoe Museum in Toronto, to weigh in on the debate (see her interview last year about high heels), and to tell us about the flip-flops the Dalai Lama gifted the museum.

When were flip-flops—or really, thong sandals—first worn? That’s the million-dollar question. The idea of a flat sandal with a thong that goes between the big toe and the second toe and then stretches across the foot on either side—I can’t think of a more elegant way of putting it—certainly dates back as far as ancient Egyptian times.

At the Bata Shoe Museum we have examples that date to the New Kingdom (16th to 11th century B.C.E.). These ancient thong sandals were clearly simple yet effective forms of footwear.

However, the flip-flop that we wear today doesn’t find its roots in ancient Egypt. Instead it has its origins in Japan, where a similar type of footwear called the zori inspired the flip-flop as we know it.

At first flip-flops were so linked to children, that for a man to wear them, it would be as if he showed up in shortie shorts.

The flip-flop is probably not even the first form of footwear ever invented. I don’t believe that there a single progression toward what we would call a shoe today. It’s not as though the thong sandal was the most rudimentary form of footwear, and finally, someone invented something more complex.

The recent Armenian shoe discovery that dates back 5,500 years ago, is more of a moccasin in construction and shows that, really, people who needed to put something on their feet based their footwear designs on what would answer their environmental and social needs. The thong sandal isn’t necessarily more simplistic or more “primitive.” In many parts of the world, all some people need to be comfortably shod is a pair of thong sandals. It’s just one of myriad examples of footwear solutions that people invented very early on.

Collectors Weekly: How did the zori become the modern flip-flop?

Semmelhack: The basic vegetable-fiber zori was a part of traditional dress in Japan for centuries. In fact, it still is an important part of formal dress for Japanese men in particular.

Women also wear zori with traditional dress, but theirs tend to be more decorative and most women’s zori feature soles with multiple layers.

How the zori came to inspire the flip-flop appears to date to World War II, when there was obviously a lot of interaction between East and West. Western soldiers would have been exposed to Japanese zori and some may have brought examples home. In addition, there are stories suggesting that Japanese soldiers, out of necessity, made zori out of old tires.

You certainly see this happening throughout contemporary Africa, where flip-flop-like shoes are being made from old tires. These rubber zori may have inspired the idea for the flip-flop, but this is where I’m still doing some research. The reason why I’m questioning this is that the Japanese production of rubber footwear was already well established prior to World War II, so the availability of mass-produced rubber zori may actually predate this story. Meaning, that rather than innovating the flip-flop, the West may simply have adopted it.

One of the most compelling stories concerning the Western flip-flop is that of John Cowie, the man considered to be the inventor of the “jandal,” which is the term for flip-flop in New Zealand and Australia. Supposedly during the 1940s, he decided to mass-produce rubber zori which he called “jandals,” short for “Japanese sandals.” These jandals were quickly embraced by beach culture in those countries in the postwar era. Before long, jandals or flip-flops could be found on the feet of surfers on the West Coast of the United States.

A challenge to this story of flip-flops entering United States dress via surfing culture, however, is the immediate postwar marketing of “foam zori,” as they were called, to American housewives. These zori were positioned to woman as something to be worn with a housecoat while puttering around the house. If one simply looks at ads from the period, it could be argued that the flip-flop moved from the house to the beach.

Collectors Weekly: Do you know how the name flip-flop came about?

Semmelhack: I think it’s an onomatopoeia, simply based on the sound that they make when worn. That’s actually one thing that I’m trying to determine right now, because when they first come into dress in the States, they are called zori. They’re not called flip-flops. They don’t get called flip-flops until the 1960s.

It doesn’t appear that the term flip-flop was ever really branded; it’s not like there was one producer who made the flip-flop. So, in answer to your question, I think the name came from that flapping noise that they make when worn. The next thing you know, that’s what everyone’s calling them.

Collectors Weekly: So when exactly did flip-flops move to the beach?

Semmelhack: I would say in second half of the 1950s. But the popularity of the flip-flop also has to do with the emergence of youth culture. We know that flip-flops have managed to worm their way into our society as something that many people wear all the time. Flip-flops were associated with beachwear, but they were something that kids were wearing when running around the house or playing outside.

Like the sneaker, the flip-flop became a type of footwear associated with youth culture in the ’60s and ’70s. If you look at the trajectory of the flip-flop, in the late ’50s and early ’60s, you have surfers wearing them as well as women and children. By the ’70s, they are a ubiquitous form of summer footwear with clear associations to youthfulness and leisure.

It is interesting that President Obama received some criticism recently for wearing flip-flops while on vacation. Obama is the first president to ever be photographed wearing flip-flops, and some deemed this look to lack presidential panache. However, he wasn’t at the Oval Office wearing flip-flops. It is clear that even though we see flip-flops in the city all summer long, they still connote a sense of leisure and youth culture. I wonder if President Bush ever wore flip-flops on vacation.

Collectors Weekly: Does this go back to the sense that it was once gauche to wear flip-flops outside of the house?

Semmelhack: Yes. A lot of sandals, in fact, were so linked to children and play, that for someone like an adult man to wear those things would be as if he showed up in shortie shorts, or something equally juvenile. There’s a kind of youthful sense to this footwear that’s also related to expressions of social standing. So it’s interesting that increasing numbers of men are very, very comfortable wearing their flip-flops.

Collectors Weekly: What is your take on the debate about whether men should wear flip-flops to work with their khakis and button-down shirts?

Semmelhack: I may be the wrong person to ask because I’m always looking at footwear. Certainly, at least where I live in Canada, we keep our feet under wraps most of the year. There’s a shocking amount of reveal that can happen over the summer months that can’t be ignored when someone dons a pair of flip-flops. But having said that, they work well, they are an efficient form of footwear.

There’s something exceptionally democratic about the flip-flop.

Clearly, since this design has been around since the times of ancient Egypt, structurally flip-flops are a durable design. They’re a form of footwear that has stood the test of time, let’s say. I can’t criticize anybody for running around in a pair, but what you put on your body makes a visual statement that another person is meant to take in instantly and determine something about you. Flip-flops still, I would argue, very loudly proclaim casualness. If that’s the statement you want to make, fine, but just be aware, or beware, of the statement you’re making.

Collectors Weekly: So is it okay for women to wear flip-flops at work?

Semmelhack: I remember in around 2001 or 2002, I was giving an interview at a press conference for a traveling exhibition. I saw a woman reporter who was in a suit and flip-flops. I was intrigued that she bothered to come to the press conference dressed in a suit but hadn’t changed her footwear. She was willing to be dressed in a traditional symbol of authority in every way, with the exception of her feet. I don’t know if it was a small expression of rebellion or youthfulness or what it was, but it was a contrast to the rest of her outfit, for sure.

But even if you’re wearing a pair of $10 flip-flops, you’re not looking your best if you don’t have your $30 pedicure. So there’s a constant demand for upkeep that keeps the money flowing. Increasingly, men are feeling that pedicure pressure, too. I don’t think as many are bowing down to it, but some are.

Collectors Weekly: Is there such as thing dressy flip-flops, like the ones with flowers or bows on them?

Semmelhack: There’s the opportunity with all the different colors these days to be matchy-matchy. There are myriad different ways for you to augment your outfit with your flip-flops. I don’t think you could find a less expensive form of footwear.

Men’s flip-flops, however, tend to be slightly more rugged and more heavy-duty, their work-shoe version, whereas women’s tend to remain playful.

Decorative flip-flops are relatively recent. Flip-flops were originally very standard in form, with the only difference being the colors that were available. That was one of the benefits of the cheap materials that they were made out of; they could be made in very cheerful colors. But you didn’t have the addition of flowers on the thong strap or heels being added until the late ’90s and early 2000s. I think that’s part of the transition of the flip-flop into something that can be worn away from vacation time.

The structure of the flip-flop has remained pretty standard. It is so functional that the only thing people have really done to the basic flip-flop is ornament them. They’ve either added some color to the foot bed—or words or design—or they’ve done something by embellishing the straps. Many have tarted up the flip-flop, but no one’s profoundly altered it. The only true alteration was the added, integral heel that was in fashion for a very short period of time. This was the only structural change, really, that anyone’s made. It’s a good thing, so why would people change it?

Collectors Weekly: When did it become more acceptable to wear flip-flops outside of the home or during the week?

Semmelhack: Sigerson Morrison made expensive heeled flip-flops at the end of the ’90s. When they made it, it created a buzz because they were also charging quite a bit for those flip-flops. They were not your average $10 flip-flop. I think they cost more than a hundred bucks when they were first offered.

The acceptability of the flip-flop is related to the hypersexualization of women’s dress. That’s why my research has been focused on the high heel. The introduction of the sandal—not the flip-flop but the toe-exposing sandal—in the 1930s, was part of a greater trend towards the “nudification,” for lack of a better term, of the female body. I feel that there has been a marked progression toward increased exposure of the female body.

What I find intriguing now is that men have begun to follow suit—perhaps not the best term here. Men are now falling in line with this increased exposure, and it could be argued this increased exposure is starting at their feet. With that increased exposure is concern about male pedicures and all kinds of grooming of the male body. I do see this as part of this larger continuum toward hypersexualization in dress. But if this exposure of the body is related to hyersexualization, I think the question—are flip-flops sexy—also needs to be asked, and I think the answer is no.

Consider the Sigerson Morrison high-heeled flip-flop. At the end of the ’90s, we certainly saw a lot of high-heeled sandal-like evening shoes for women that exuded erotic appeal. And yet, somehow, that exact same structure, the heeled flip-flop structure wrought in inexpensive plastic, wasn’t. I think that the materials used to make flip-flops, their garish colors and their consistent association with play, has kept the flip-flop from really becoming sexy. On the cover of “Playboy,” you will see women in high heeled thronged sandals, but you don’t see them wearing a pair of flip-flops.

Collectors Weekly: The other craze of the past decade has been for Crocs.

Semmelhack: Yes, but I don’t think they were worn to augment sex appeal. Crocs were embraced so quickly, they came to rival the flip-flops. People wore them in the same way that they wore flip-flops—casual dress, throw them on, run around, do your stuff. They established that you’re part of the trend, the fad, but they weren’t integrated into the more serious wardrobe.

I don’t know how many Crocs were worn to work. They certainly were worn to work in hospitals and places like that, where they had some kind of functionality. Very quickly Crocs did attempt to morph into multiple different types of Crocs as you mentioned—Mary Janes, high-heeled—but it didn’t stick at all.

The flip-flop is similar. It doesn’t have the exact same trajectory, but I think that it doesn’t need any structural change. The original Croc was successful because it was comfortable, and the flip-flop’s the same way. It doesn’t need to be morphed into, say, the Brogue flip-flop for the businessman.

Collectors Weekly: Are the formal, fiber thong sandals in Japan woven?

Semmelhack: Yes. There’s a bunch of different ways of making them, but yes, they’re woven together. Sometimes the plaiting—it’s not really weaving—is exceptionally fine, just gorgeous, gorgeous pieces.

There are versions of this footwear in many different cultures, but I wouldn’t call those versions flip-flops because flip-flops connote really cheap, bright-colored sandals. These thong sandals can be quite sophisticated.

In India or in Africa, the Akan people wear some shoes that are structurally similar. For the Asantehenes, who are the regional rulers, their sandals often feature very wide straps, sometimes covered with expensive textiles. Most often, however, they’re leather and they’re covered with gold foil or gold-leafed covered wooden-carved symbols. They can be really elaborate, and they’re absolutely beautiful.

Among the Tuareg and the Hausa, there’s again this basic sandal structure created, although the foot bed is much wider—this is because they’re often walking on sand. The shoe is designed to facilitate movement across a sandy surface that gives. They can be incredibly beautifully decorated with leather work and pigmentation.

Collectors Weekly: What about the flip-flop’s impact on your feet?

Semmelhack: Well, they’re great to wear in the gym shower, but in terms of daily wear, I am sure you will not find a podiatrist who will advocate them. But the history of footwear pretty much shows that people aren’t that interested in having footwear that is absolutely perfect for their stance and their mobility. Footwear is more often about looking good. Comfort and actually helping with gait and mobility is infrequently the focus of footwear.

Collectors Weekly: What does the flip-flop craze say about our culture?

Semmelhack: There’s something exceptionally democratic about the flip-flop. You can buy a pair for a dollar. It is also a very unisex form of footwear. We’ve discussed gender differences in some flip-flop structures, but you can still go to Old Navy and everybody in the family can buy the exact same blue flip-flop. And you could walk out of the store with footwear for everybody for under—I don’t know—25 bucks.

Versions of those same blue flip-flops are also worn around the world. In Europe and India, China and Mexico, people are running around in the exact same flip-flops that you and I are wearing to the beach. Again, that’s hugely democratizing. I can’t think of another moment in time when so many people around the world were wearing the exact same type of footwear.

Even sneakers, which I would argue are a close competitor in terms of democratized fashion, can’t match the ubiquity of the flip-flop because there’s still a huge difference in the types of sneakers that are available and worn. The humble flip-flop, however, is pretty much standard around the world.

Collectors Weekly: Even the Dalai Lama wears them, right?

Semmelhack: Yes, and believe it or not, the pair that the Dalai Lama recently donated to the museum were Bata flip-flops. The focus of our collection is not Bata footwear, but the Bata company does makes many, many flip-flops, so it makes sense that he would own a pair.

Collectors Weekly: Will rubber flip-flops ever become collectible?

Semmelhack: They could, potentially, but at this moment, like I’ve said, there still isn’t the same kind of brand identity as there is with sneakers. “I’m wearing my Nike flip-flops.” “I’m wearing my Adidas flip-flops.” “I’m wearing my Prada flip-flops.” We still aren’t at that point with flip-flops. We’re just wearing our flip-flops. In order to make them collectible, maybe flip-flops need to cease being so democratic.

(Photos from the Bata Shoe Museum. Cake Boss photo from Cake Walk. Sigerson Morrison from Texasdna)