I'm sure that there were wonderful voices before Emmylou Harris. But, when I first heard Emmylou sing in the mid-1970s, I couldn't imagine that anyone possibly could have a more beautiful or sweeter voice. She's just angelic. And, well, perfect.
Emmylou was "discovered" in 1971 by Chris Hillman (then with the Flying Burrito Brothers, but best known for his work with the Byrds) at Clydes in Washington, D.C. Hillman recommended Emmylou to his former bandmate, Graham Parsons, and soon thereafter Emmylou was singing harmony with Parsons - until he died from a drug overdose in a hotel room in California. Emmylou then began work on Pieces in the Sky, her major-label solo debut, which is a collection of covers ranging from Merle Haggard to the Beatles. And she followed that up with Elite Hotel in 1976 with her new band, the Hot Band, which featured James Burton and Glen Hardin, most famous for playing with Elvis Presley, and Rodney Crowell, who played rhythm guitar and sang backing vocals.
Since then she has a amazing career, singing with legendary artists such as Dolly Parton, Linda Ronstadt, George Jones, Willie Nelson, and Mark Knopfler, among many others. And, of course, she joined forces with the Band for her appearance in The Last Waltz in 1978.
Emmylou was "alt-country" before anyone even knew there was a thing called "alt-country. She's amazing. And here is Song Three: Emmylou Harris singing Together Again with the original Hot Band" in 1976.