Well, despite the celebrated images from the mosaics in Piazza Armerina, of the ancient Roman girl wearing what looks like a bikini, the answer is, “not really”. The ancient Roman girls weren’t even first to wear what to our eyes looks like a bikini. However, the fact that we seem to find “bikinis” in ancient depictions should make us rethink our hubristic bias that we in modern times have invented everything and that people in ancient times didn’t know how to live.
Archaeologists have found evidence of bikini-like garments that date to as far back as 5,600 BC. That’s roughly 5,000 years before the Romans did so. In the Chalcolithic era of around 5600 BC, the mother-goddess of Çatalhöyük, a large ancient settlement in southern Anatolia, was depicted astride two leopards while wearing a bikini-like costume.

Two-piece garments worn by women for athletic purposes are depicted on Greek urns and paintings dating back to 1400 BC. In fact, even just the notion that women participated in sports in the ancient world should make us sit up and take notice. Today we tend to imagine women in the ancient world as being practically sequestered in their homes, spinning, weaving and having babies. But this is a gross oversimplification of their role.
Active women of ancient Greece wore a breast band called a mastodeton or an apodesmos, which continued to be used as an undergarment in the Middle Ages. While men in ancient Greece abandoned the perizoma, partly high-cut briefs and partly loincloth, women performers and acrobats continued to wear it.
In the famous mosaics to be found at Villa Romana del Casale in Piazza Armerina, the girls who seem to be wearing the “bikini” are Roman and the so-called bikini had already been around for at least 5,000 years by then.
So, what did the Roman girls wear it for? In the artwork “Coronation of the Winner” done in floor mosaic in the Chamber of the Ten Maidens (Sala delle Dieci Ragazze) the bikini girls are depicted weight-lifting, discus throwing, and running.

Having established that the modern world did not invent the bikini, we still need to consider how it became so popular in the modern world. It is commonly dated to July 5, 1946, when, partly due to material rationing after World War II, French engineer Louis Réard introduced the modern bikini, modeled by Micheline Bernardini.
Also thanks to the time and the War, Réard named his design for the Bikini Atoll, where the first post-war tests of the atomic bomb were taking place, because the word was in the news a lot at that time, and frankly, he simply must have liked the sound of it. Talk about serendipity!
Famous actresses such as Brigitte Bardot and Ava Gardner wore the bikini in the 1950’s but it wasn’t until Ursula Andress made her spectacular exit from the Caribbean Sea in the James Bond classic, Dr. No, that the bikini really took off (no pun) and it became mainstream beachwear—but for a couple of decades more, still only for the most daring.