If anyone warrants a footnote in history, it’s Mahalia Jackson. If anyone deserves a modicum of recognition for what transpired before 250,000 people crammed at the foot of Washington's Lincoln Memorial on a sweltering afternoon 50 years ago, it’s surely Mahalia Jackson.Yet her story remains unsung, her involvement in one of the greatest speeches of all time unheralded. Jackson was a gospel singer blessed with a contralto voice, 30 albums, sales in the millions. Yet she was more than that, recognized as an activist who lent her formidable presence to the awakening civil rights movement, described as "the most powerful black woman in the US."Born in 1911 into a New Orleans household which included 13 family members and a dog, she was so bow-legged, doctors wanted to break her legs. Fortunately, an aunt intervened.Vic Alhadeff is chief executive officer of the NSW Jewish Board of Deputies in Sydney, Australia. Twitter: @VicAlhadeffThe first gospel singer to perform in New York's Carnegie Hall, she sang at President John Kennedy’s inaugural ball. "God touched the vocal chords of this great woman,” observed historian Noel Serrano.Meeting Martin Luther King Jr. at a Baptist convention, he invited her to join a protest in Montgomery, Alabama, against bus segregation. Ignoring death threats, she agreed. She frequently encountered prejudice and had been thwarted by white owners and estate agents when trying to buy a home in Chicago. When she eventually succeeded, shots were fired at her windows.Jackson began to accompany King to rallies in the segregated south, using her voice to “break down some of the hate and fear that divide white and black."August 28, 1963 was designated for a March on Washington DC. The civil rights movement now featured protests, water cannons and allegations of "un-American" activities. King had been arrested 13 times. Relaxing in the Willard Hotel the night before, he discussed his speech with staffers, after speech writer Clarence Jones had prepared a draft. With three networks screening the rally, it would be his first nationwide exposure. He duly retired to finalize a presentation he hoped would resonate "like the Gettysburg address." "I am going upstairs to counsel with my Lord," he said dramatically. "See you tomorrow."He got to bed at about 4 a.m. There was no reference in his speech to dreaming - a refrain he had used previously, but with no effect.Thousands poured into Washington, including Charlton Heston, Sidney Poitier, Sammy Davis Jr., Burt Lancaster, James Garner, Marlon Brando and Paul Newman. The speakers were limited to five minutes each, but all overran. Overcome by humidity, people began to drift away. King was the last of 16 speakers. Immediately preceding him was American Jewish Congress president Dr Joachim Prinz. "When I was rabbi of the Jewish community in Berlin under the Hitler regime, the most important thing I learned was that bigotry and hatred are not the most urgent problem,” he noted. “The most urgent, the most disgraceful, the most shameful and the most tragic problem is silence."Wearing a black suit, white shirt and black tie, King's turn finally came. His delivery was unremarkable. "Go back to Mississippi,” he intoned. “Go back to Alabama, go back to South Carolina, go back to Georgia, go back to Louisiana."Suddenly, a sharp cry rang out. Mahalia Jackson, one of the supporters clustered near him, spontaneously shouted: "Tell them about the dream, Martin!"King droned on. "Go back to the slums and ghettos of our northern cities, knowing that somehow this situation can and will be changed."Jackson again, more urgently: "Tell them about the dream!" He did. He paused; and then produced one of the defining oratorical flourishes of the 20th century. Placing his notes on the lectern, he transformed from pedestrian lecturer into the epitome of inspiration, his tone taking on a soaring cadence and imparting a message whose power and relevance have stood the test of time.Gripping the lectern, he stated: "So even though we face the difficulties of today and tomorrow, I still have a dream."At which point he launched into the magnificent poetry which captured like no other the self-evident truth that all people are created equal, that black and white should be able to live together, that individuals should be judged not by the color of their skin, but by the content of their character. Although King was “known before he stepped up to the lectern," noted Clarence Jones, "he stepped down on the other side of history."King was assassinated in 1968; Jackson sung “Take My Hand, Precious Lord” at the funeral. She died four years later, and 50,000 people filed past her mahogany, glass-topped coffin to honor the queen of gospel whose unforeseen outburst paved the way for an oratorical masterpiece whose eloquence reverberates 50 years later.