The night before the March on Washington in 1963, Martin Luther King Jr asked his aides for advice about the speech he was due to make the next day. “Don’t use the lines about ‘I have a dream,’” Wyatt Tee Walker told him. “It’s trite, it’s cliché. You’ve used it too many times already.”

King had indeed employed the refrain several times before. It had featured in an address just a week earlier at a National Insurance Association fundraiser in Chicago and a few months before that at a huge rally in Detroit. Like most of his speeches, both had been well received. But neither had been regarded as particularly momentous.

While King, by this time, was a national political figure, relatively few outside the black church and the civil rights movement had heard him give a full speech. With all three television networks offering live coverage of the March for Jobs and Freedom (the biggest event of its kind in the country’s history), this would be his introduction to the nation. He wanted a speech to fit the occasion.