By September 12, 1965, when The Beatles performed for their final time on "The Ed Sullivan Show," the band was at the height of their popularity amid the cultural phenomenon known as Beatlemania. This performance came shortly after the release of their album "Help!" in August 1965, which showcased their continued evolution in music, featuring a mix of pop and more sophisticated songwriting. Notably, this appearance also occurred just a day before their groundbreaking concert at Shea Stadium, marking a significant moment in live music history as one of the first major stadium concerts. The Ed Sullivan Show played a crucial role in their rise, having introduced them to American audiences earlier in 1964. This final performance was viewed by millions, encapsulating the immense impact The Beatles had on popular culture and the music industry during this vibrant period of their career.