On the week of January 1, 1966, Simon and Garfunkel started a weeklong run at Number One on the Billboard charts with "The Sounds Of Silence." They were knocked out of that spot on January 8 by the Beatles' "We Can Work It Out," but returned to the Number One slot for one more week on January 22.
Simon and Garfunkel started as Tom and Jerry, Everly Brothers wannabees from Queens, New York. They had a minor 1957 hit with "Hey, Schoolgirl" (Number 49 on Billboard charts), and seemed destined for footnote status in the saga of rock and roll's golden age. After years apart, they resurfaced under their real names as topical folk singers. In the fall of 1964, Simon and Garfunkel released an acoustic album called Wednesday Morning 3 A.M., which included an arrangement of "The Sounds of Silence" that only included vocals and acoustic guitar.
With the folk revival all but over, the record was universally ignored and the duo again split. Folk rock hit a year later, and Wednesday Morning 3 A.M.'s producer Tom Wilson (concurrently helping Bob Dylan "go electric") overdubbed a rock backing track on "The Sounds of Silence," remixed it, and had it released as a single. Paul Simon was kicking around England as an obscure solo artist when he found out that he and Art Garfunkel, now in graduate school in New York, had the Number One song in the U.S. They hastily re-formed and became card-carrying folk rockers.