While theater has long led other creative genres in this regard, it’s done so partly out of good intentions and partly out of necessity—the canon is almost entirely plays written by white men featuring white characters, many of which had to be performed by all-male casts when they were first produced. As the demographics of acting schools shifted in the 20th century, there were an increasing number of classically trained performers looking to tackle theater’s most challenging roles. “The theater was the one place during the McCarthy era where black actors could work,” says Michael Kahn, the artistic director of the Shakespeare Theatre Company. “So there’s always been a more progressive attitude in theater than film. And history, in particular, comes even more alive when you relate it to the community who’s looking at it.”

There’s also a fluidity regarding gender in Shakespeare’s plays that stems from the fact that women weren’t allowed on English stages until the 17th century. The suspension of disbelief required to imagine a male actor being the virginal 13-year-old Juliet, for example, has long made Shakespearian productions more receptive to imaginative casting than many modern shows. “People expect it in Shakespeare,” says the director Julie Taymor, whose recent movie adaptation of A Midsummer Night’s Dream featured black actors playing Helena and Oberon. “It’s oddly enough with him, the great genius playwright, where for a long time now it’s been possible to do multi-racial casting without anyone blinking an eye, or thinking of his characters as a black person or a white person or an Asian person. They’re just characters.”

Theater’s also had problems when it comes to casting, with the tradition of blackface being prevalent through the 1950s. In 1964, Lawrence Olivier painted his face with ludicrous black makeup to play Othello at the National Theatre in a production whose film adaptation was likened by The New York Times to a minstrel show. It was only this year that the director Bartlett Sher decided not to use blackface for his production of Otello, following the example of a 2014 production at the English National Opera, which was the first major production to cast a white singer in the role and not have him wear makeup. While theater’s led in terms of colorblind casting, it’s taken much longer for the notion to catch on that white actors shouldn’t alter their appearance to try and look like they’re of a different ethnicity.

Nor is casting actors of color in traditionally “white” roles without controversy. In 1997, the playwright August Wilson delivered a speech titled “The Ground on Which I Stand,” in which he analyzed the overarching whiteness of theater in the U.S., stating:

We do not have any theaters of comparable size, quality, and financial resources as our white counterparts that would allow us to support our artists and offer them meaningful avenues to grow and develop their talents and make the contributions to the body of world art of which they are capable. What we have instead is a furtherance of white hegemony and a truncation of our possibilities. Money spent “diversifying” the theater, developing black audiences for white institutions, developing ideas of colorblind casting, only strengthen and solidify this strangle-hold by making our artists subject to the paternalistic notions of white institutions, allowing them to dominate and control the art.

The speech electrified American theater at the time, and led to an impassioned debate over whether black actors should take on historically white roles, or work to create their own canon, as Wilson stated, thus championing “our own causes, our own celebrations, and our own values.” One of Wilson’s most outspoken critics at the time was Robert Brustein, who founded the American Repertory Theater. “Refusing to let black actors play anything but black parts seems narrow to me,” Brustein says. “And it would have robbed us of some of the great performances of our time. One thing we must not do, in theater, is exclude anyone because of race, or because of anything.”