The 1967 album cover for Sgt. Pepper’s Lonely Hearts Club Band was not the first artwork that Peter Blake made for The Beatles. Three years earlier, Paul McCartney had asked the British Pop artist to “paint something good” for his newly purchased Scottish farmhouse. (Blake eventually presented him with a painting inspired by the majestic stag from Sir Edwin Landseer’s 1851 work The Monarch of the Glen.)

But it was the Sgt. Pepper’s cover, with its technicolor marching band and star-studded crowd, that came to define Blake’s legacy. Today, the 85-year-old artist regards its fame with mixed emotions. “You get stuck with a certain kind of image that will never lose you,” he said in 2007. “I’m proud of it, but I’ll never get away from it.”

It’s true that the cover represents just a fraction of Blake’s eclectic career—which he has developed over the past seven decades and traces back to youth, when he flunked a grammar school entrance exam. As a result, at the age of 14, he applied to the Junior Art School of Gravesend Technical College instead, and, despite not having shown a particular interest or natural capacity for art, enrolled there. Blake spent the next four years honing artistic skills like typography, illustration, graphic design, life drawing, silversmithing, and more.

While Blake’s legacy may forever be dominated by his album cover, he’s taken a firm stance in defining the twilight years of his career. “Usually other people decide when your Late Period is or was, but rather than wait for anyone else, I’ve decided very consciously to have mine now,” he told the Guardian in 2006. “I know I’ve done pretty much everything it was reasonable to expect, and maybe sometimes I’ve done a little more than that.”

When Blake and Haworth stepped in, the band had already dreamed up the marching band theme. Blake suggested a “magical” audience in the background of the photograph, “the kind of crowd that you could never bring together.” He collected a list of names from three of the four Beatles (John Lennon famously included Adolf Hitler among his suggestions, though the artists obscured him in the finished work) and added a few art-world personalities of his own: Light and Space artist Larry Bell, and the creator of the Watts Towers in Los Angeles, Simon Rodia.

In all, Blake and Haworth were paid £200 for their work on the now-iconic cover—a nominal fee that’s still a sore spot for Blake. (“Even the people that did the flowers were paid more!” he later griped.) The piece encapsulated exactly what Blake had been trying to do in his wider artistic practice—make works with the “directness and distribution of pop music,” he explained. With Sgt. Pepper’s, “if you bought the record you also bought a piece of art on exactly the level that I was aiming for.”