One hundred years ago, in May 1923, British radio listeners heard something entirely new: a full-length radio drama. The BBC production of Shakespeare’s Twelfth Night transformed the medium and showed that there was a new way to tell the celebrated playwright’s stories. This paper will explain how it was done, what effect it had on the airwaves and the legacy left by this performance that continues to this day. It will do this by examining first-hand accounts of the production from those taking part and those who heard it, as well as those involved in subsequent productions. It will show that this experimental broadcast had all the ambition of modern audio drama, but without the sophisticated technology. And it will show that while for many years the work involved in getting this play to air was attributed to a man, it was in fact a woman who was behind this hugely significant moment in radio history. This broadcast of Twelfth Night was the first of more than 400 productions of Shakespeare’s plays on BBC radio, which are still being produced. It was also a trailblazer for similar productions in America, Canada and Australia in the decades that followed. In addition, this first attempt at radio drama was the precursor of the audio drama boom that we are seeing today from companies like Audible, as the inheritors of this pioneering BBC production continue to transform our listening in the twenty-first century.