"Come Together" together with "Something" was released in the United States on October 6th, 1969 as a direct result of Allen Klein's management of the Beatles. It was his first act, intended to bring them more cash flow. Subsequently on November 29th BOTH titles reached number one. The first time this sort of thing ever happened since Elvis Presley's "Don't" and "I Beg Of You".
It was also the Beatles 18th number one single, breaking Elvis's record of 17 number one singles.
"Wedding Bell Blues" by the Fifth Dimension was number one before "Come Together/Something". "Come Together/Something" was number one for one week and then was supplanted by Steam's "Na Na Hey Hey Kiss Him Goodbye".
