December 26th, 1963 was the official American release of the first two singles by The Beatles, although some sources state that their songs began playing on the radio much earlier. "I Want to Hold Your Hand" became the first number one single for the Beatles on the American charts. The B-Side single, "I Saw Her Standing There" only rose to the #14 spot, but the Beatles were here to stay.
In the early years, the Beatles mainly appealed to the shrieking teenybopper set, but as time went on they evolved from a pop sensation into a true rock band, writing songs that reflected the radical cultural shifts occurring in the mid to late 1960s.
Although they broke up in 1970, the Beatles remain one of the most successful music groups of all time. Twenty of their singles reached the number one spot on Billboard's Hot 100, giving them the record for most number one hits and making them number one on Billboard's list of top 100 artists of all time.