Johns’s debut solo exhibition at Castelli’s gallery on the Upper East Side 10 months later is now legendary. His work was a series of familiar symbols — American flags, targets, numbers — painted on newsprint with encaustic, in which pigment was mixed with heated beeswax. (This was, at the time, a truly esoteric method, best known from the Fayum mummy portraits from the first couple centuries A.D.) The show now has the reputation of doing nothing less than announcing the death of Abstract Expressionism. This is reductive, of course — de Kooning and others would continue to have long and successful careers after the arrival of Johns — but his work did dramatically reimagine the possibilities of what could happen on a canvas. If Abstract Expressionism was a melodramatically psychological exercise, with each splash of paint communicating some anguished search for American identity in the midst of the Cold War’s atomic glow, here was something cool and detached, familiar and yet forever unknowable. It was as if Marlon Brando had driven his motorcycle onto the set of a Clark Gable movie.

At 27, Johns became an overnight success and an indecipherable oracle of modern America. He was clearly saying something, but what? Was his American flag a canny critique of Eisenhower-era imperialism? Was it an ironic tribute to his namesake, someone who quite literally died for the flag? Was it a tautological exercise, a heroic attempt to separate the flag from its context? Johns has only ever given the same story: One night, in 1954, he dreamed of painting a flag, and the next morning he got up and started doing it. He spent much of the next five years painting the flag in various forms, and then, for a while, mostly stopped. When asked about this in a 1963 interview with a German magazine, he said: “They added two stars,” a reference to Alaska and Hawaii becoming states in 1959. “Since then, the design does not interest me anymore.”

IT’S TEMPTING TO think of Johns’s career in two parts: with Rauschenberg and post-Rauschenberg. Johns may not be forthcoming with details of his personal life, but he is an expert self-mythologizer, and there is likely no romance between two visual artists in postwar America that occupies the same level of importance in the public’s imagination as Johns’s with Rauschenberg. Between 1955 and 1961, the two lived and worked in proximity to one another, first on Pearl Street and then, in 1958, when the Pearl Street building was condemned, over a hero sandwich shop at 128 Front Street, this time with Johns upstairs and Rauschenberg downstairs. They shared ideas, motifs and materials and ended up carving a path for much of the art that has emerged in the 60 years since. Most of the subsequent artistic milestones one can think of — from Andy Warhol’s first Campbell’s soup cans in 1962 to Tracey Emin putting her own bed on view inside the Tate Gallery in 1999 to Kerry James Marshall’s use of collage, printing and other variables on the canvases of his early paintings — originated with the work Johns and Rauschenberg produced during these years.

Rauschenberg’s “combines,” a series of works the artist began making in 1954 that combined elements of painting and sculpture (Johns described them as “painting playing the game of sculpture”), took contemporary art down from the wall and into new territory entirely. Johns was often present in these works, sometimes spiritually, often literally. One, “Short Circuit” (1955), included a flag painting by Johns inside a compartment with a small door. Another combine, “Untitled” (circa 1954), sometimes referred to as “Man With White Shoes,” was a wooden structure that resembled a front porch, partially painted and mounted with objects ranging from a taxidermied hen to personal ephemera: a letter from Rauschenberg’s son, photographs of his parents, a picture of Johns. In 1958, Johns expanded on the strange familiarity found in his paintings of flags and numbers by making sculptures of everyday objects (light bulbs, beer cans) that he cast in bronze, prefiguring Warhol’s fascination with mass production and pop culture symbolism by several years. His paintings, like Rauschenberg’s, began to incorporate sculptural elements, as with “Target With Four Faces” (1955), which included the familiar target but with four plaster casts of an eerily expressionless face, cut off just below the eyes, peering out from beneath a wooden slat affixed to the top of the painting.