with John Lennon, Paul McCartney, George Harrison, and Ringo Starr, they became widely regarded as the greatest and most influential act of the rock era. Rooted in skiffle and 1950s rock and roll, this band later experimented with several genres, ranging from pop ballads to psychedelic rock, often incorporating classical elements in innovative ways. In the early 1960s, their enormous popularity first emerged as "Beatlemania", but as their songwriting grew in sophistication they came to be perceived as an embodiment of the ideals shared by the era's sociocultural revolutions.