Two days before the Olympic flame entered Tokyo’s main stadium for the opening ceremony, members of the women’s soccer teams staged protests.

It started when all of the members of the British team knelt to protest racism. They were joined by their Chilean opponents. Then the U.S. and Swedish players, and even a referee knelt before their match, as did the New Zealand players before their match with Australia, while the Australians posed for a pregame picture with the country’s Indigenous flag to highlight Aboriginal disadvantage. Many more protests are expected during the course of the Games, despite the efforts of the International Olympic Committee (IOC) to discourage political protests. In doing so, athletes will be upholding a time-honored Olympic tradition. For over a century, activists have used the Games to stage political protests, and this strategy of athlete activism has only gained more support and visibility with the growing attention generated by the Games themselves.

The modern Olympic Games were a product of a wave of 19th-century globalization. From 1870 to 1914, not only was there a blossoming of empire and international trade, but also of humanitarian and peace movements, of which the Olympic movement was an example. Its founder, Baron Pierre de Coubertin, believed that Olympiads were a way to communicate “love for concord and a respect for life.” So it was not surprising that activist athletes saw the Olympics as a legitimate forum to promote those values whenever they saw them violated.

The first protest was staged at the 1906 Olympics in Athens. During the medal ceremony, the second-place finisher in the long jump, Irishman Peter O’Connor, shinnied up the 20-foot flagpole and unfurled a large green flag embroidered with a shamrock, harp and the words “Erin Go Bragh” (Ireland forever), the popular maxim of the Irish independence movement. Ever since the brutal invasion of Ireland by Oliver Cromwell in the mid-17th century, there had been no concord between England overlords and the Irish. For O’Connor, the Olympics were an opportunity to draw attention to this injustice. It worked, generating media coverage in Britain and the United States.

In 1952, during the opening ceremony in Helsinki, Barbara Rotraut-Pleyer, a peace activist, invaded the field. Wearing white flowing robes and with her red hair streaming behind her, she did a lap of the infield before stepping onto the officials’ rostrum. She was apprehended before she had an opportunity to grab the microphone and give her prepared speech demanding “the end of all cold and hot wars.” But her dramatic gesture generated global media attention and gave her an international profile. Indeed, in the years that followed, she met world leaders with her messages of peace.