While music historians—and fans of either or both—may be willing to offer an opinion, the question cannot be definitively answered. The fact is that popular music today would not be what it is had it not been for both Elvis Presley and the Beatles. And the influences of both are still felt.

Elvis Presley (1935–1977) brought to music an exciting and fresh combination of country, gospel, blues, and rhythm and blues music, and topped it all off with a style and sense of showmanship that dazzled young audiences. His first commercial recording was “That’s All Right, Mama” in 1954, which was followed in 1956 by the success of “Heartbreak Hotel.” Between 1956 and 1969 he had 17 number-one records. Presley defined a new musical style—and an era.

Among those the American Presley had influenced were four English musicians who called themselves the Beatles. Originally founded as the Quarrymen by John Lennon (1940–1980) in 1956, the group became the most popular rock-and-roll band of the 1960s. Their first single was “Love Me Do,” released on October 5, 1962, and producer George Martin was encouraged that the Beatles could produce a number-one record. In 1963 they did: “Please Please Me” was released in Britain on January 12 and was an immediate hit. Other hits off their first album included “She Loves You” and “I Want to Hold Your Hand.” The follow-up album, With the Beatles, was released in 1964 and established them as Britain’s favorite group.

Already popular in their homeland, “Beatlemania” began in the United States on February 7, 1964, when the mop-topped “Fab Four” (Lennon along with Paul McCartney, b. 1942, George Harrison, 1943–2001, and Ringo Starr, b. 1940) arrived at New York’s Kennedy International Airport and were met by a mob of more than 10,000 screaming fans and 110 police officers. Two days later, on February 9, the Beatles made their legendary appearance on The Ed Sullivan Show. By April the group held onto the top five positions on the U.S. singles charts. The British Invasion had begun.

In their early years, the Beatles brought a new energy to rock and roll and picked up where Presley, Buddy Holly, and Little Richard had left off. The instrumentation and orchestration of Beatles songs (for which their producer George Martin deserves at least some of the credit) were innovative at the time, and are common for rock music today. Their rock movies, A Hard Day’s Night (1964) and Help! (1965), were a precursor to the music videos of today. When the band decided to break up, the April 10, 1970, announcement proved to be the end of an era.