Martin Luther King Jr., Italian opera, Pepsi and prison gangs— we reveal the surprising stories behind the King’s classic songs.

his month marks 45 years since rock ’n’ roll lost its king, Elvis Presley—and he’s rarely been out of the spotlight since. This summer, his legend came back to big-screen life in director Baz Luhrmann’s extravagant hit film Elvis. But the story of Elvis would have never had such profound and enduring resonance without the excitement and emotion in his songs. “As a singer and an artist, Elvis was revolutionary,” says Jerry Schilling, a key member of the star’s tight-knit inner circle, cheekily known as the “Memphis Mafia.” “His music came from so many sources: gospel and country, R&B and rock, or even from opera. He was

Table to take any kind of music and make it his own.” “His appeal is rooted in so many factors,” says Alanna Nash, who has written four books related to the star—including The Colonel (2010), about Presley’s complicated relationship with his manager, “Colonel” Tom Parker. “The depth of his artistry, the originality of his sound, as well as his looks and his sexual daring.”

The best of Elvis’ songs and performances drew on all those elements. Here are the stories behind 15 of his songs that have meant the most.