Robert Indiana, a towering figure in the American Pop art movement whose LOVE sculpture became one of the most reproduced works of art of the Modern era, has died at the age of 89.

Indiana, whose real last name was Clark, was already enjoying critical and market success when he debuted his LOVE series at the Stable Gallery in New York in 1964. That same year, Indiana’s work was shown alongside that of Andy Warhol at the World’s Fair in Queens.

But that simple, four-letter sculpture would go on to overshadow the rest of the artist’s oeuvre and prompted some critics to dismiss him as a one-trick pony. Indeed, the fact that this image made him world-famous was something of a double-edged sword. While LOVE was reproduced on 330 million postage stamps, allowing Indiana’s art to travel the world, it was also reconfigured in countless other forms that he never authorized—or profited from.

His lawyer told the New York Times that Indiana died on Saturday of respiratory failure. Just one day earlier, a company that had worked with Indiana for years filed a lawsuit against a competing art seller and the artist’s caretaker for allegedly isolating the artist and producing unauthorized reproductions of his work.

Despite the ubiquity of his most famous image, Indiana has been an elusive figure in the art world for decades. In 1978, disillusioned with the New York art world—and the harsh and unfavorable reviews he was receiving—he retreated to Vinalhaven, an island off the coast of Maine, which is only reachable via an hour-long ferry ride.

Indiana’s fortunes began to change in the past two decades, thanks in part to the tireless efforts of his art dealers. A wave of exhibitions helped broaden the public’s understanding of Indiana’s work, which included far darker interpretations of the American dream. In the 1960s, he created diamond-shaped paintings with the words “Eat” or “Die,” as well as works inspired by the Civil Rights movement.

Robert Indiana in his studio, Vinalhaven, Maine. Photograph courtesy of Dennis and Diane Griggs.

These shows helped boost both critical and popular attention as well as sales (a boon for Indiana, who reportedly only received $1,000 for designing the LOVE stamp and did not bother to trademark the image when he first created it). They also helped him secure prestigious public art commissions in Midtown Manhattan and elsewhere.

Eventually, Indiana himself seemed to take a more sanguine view of the LOVE imagery that made him so famous, reportedly assembling a massive collection of tchotchkes and knockoffs inspired by the logo. Before dealers and licensing agents sought to pursue infringers and cash in on the image in the ’90s, he had been unable to capitalize on the millions of mugs, keychains, and trinkets for which he was sometimes unwittingly branded a sellout.

His revived career culminated with a major and aptly titled retrospective “Beyond Love” at the Whitney Museum of American Art in 2013. “His paintings are gateways between the visual and the verbal, the private and the public, the physical and the metaphysical, and the conscious and the unconscious,” Ken Johnson wrote in a review of the exhibition. “Richly ambiguous, they unsettle fixed categories. And they are ravishing to behold.”

News of the artist’s death comes at a moment of particular tumult for Indiana and his legacy. Friends and colleagues had recently grown so concerned about their inability to reach Indiana that they had alerted local authorities, according to Luke Nikas, an attorney for a fine art company that filed a lawsuit against Indiana’s caretaker and a competing art seller.

Robert Indiana’s Love. Photo: Wikipedia.

On Friday—one day before Indiana’s death—the Morgan Art Foundation, which has worked with the artist for more than 25 years and funded production of his work, filed a federal lawsuit targeting art seller Michael McKenzie, his editions company American Image Art, the artist’s caretaker Jamie Thomas, and Indiana himself.

Their complaint alleges that McKenzie and Thomas had commandeered Indiana’s phone and email account in recent years, ultimately cutting off direct communication between the elderly artist and his friends and colleagues. The foundation’s advisor Simon Salama-Caro and his son, Marc, became alarmed when, upon attempting to visit or communicate with him, they received profanity-laced messages telling them to “F**K OFF” or that Indiana did not want to receive visitors, according to the complaint, a copy of which was obtained by artnet News.

The New York Times reported that attempts to reach Indiana at his residence in Vinalhaven—an 1870s-built lodge known as the Star of Hope that was formerly used by an international fraternal organization known as the Independent Order of Odd Fellows—had been unsuccessful.

Nikas told artnet News that he reported the alleged exploitation to local authorities on Friday, at the same time the lawsuit was filed. In response to the suit, McKenzie told the Times: “Bob does not want to see anybody. He just feels, like, ‘I am old, I need to eat a lot of soup. I am trying to keep it together.’”

The lawsuit also alleges that McKenzie and Thomas have been overseeing the production and distribution of unauthorized works and even fakes. The Morgan Art Foundation Limited, a company listed in the Bahamas, has sued the pair for copyright infringement, violation of the Visual Artists Rights Act, defamation, breach of contract, and other claims.

Earlier today, McKenzie told artnet News via email: “Numerous counterclaims will be filed and we will have more to say shortly.” His attorney did not respond to a request for comment by publication time.

“The sad news of Indiana’s death only underscores the importance of the litigation and what it seeks to accomplish as the art world rightfully examines the considerable contributions Indiana made through his life’s work,” Nikas told artnet News.

Ahead of the artist’s Whitney retrospective, this reporter spoke with American art expert John Wilmerding about Indiana’s life and work. When the LOVE sculpture was first exhibited, Wilmerding recalled, “It had such originality with its tipped ‘O‘ and this radical kind of punch. Nobody had seen a word treated as a block before.”

Of the fact that the image eventually overshadowed and at least temporarily dampened Indiana’s legacy, Wilmerding added: “It remains the great central paradox of his career.”

UPDATE: A previous version of this article incorrectly stated that the lawsuit over the allegedly unauthorized reproduction of Indiana’s work had been filed by the Morgan Art Foundation’s advisor Simon Salama-Caro and his son, Marc. The lawsuit was in fact filed by the Morgan Art Foundation itself.