NEW YORK • Hal Prince, the Broadway royal and prodigious Tony winner who produced or directed (and sometimes both) many of the most enduring musicals in theatre history, including West Side Story, Fiddler On The Roof, Cabaret, Sweeney Todd and The Phantom Of The Opera, the longest-running show in Broadway history, died on Wednesday in Reykjavik, Iceland. He was 91.

A spokesman said he had been on his way home to Manhattan from his residence in Switzerland when he died in Iceland after a brief illness.

Prince began working in theatre in the halcyon days of Broadway, when Cole Porter and Rodgers and Hammerstein were its songwriting kings, the stage musical was a robust American art form and theatre songs were staples of the airwaves.

His contributions were prolific, persisting through challenging eras - when rock 'n' roll threatened to make show music irrelevant and when corporations such as Disney miniaturised the impact of the independent producer.

His singularly significant role in shaping the Broadway musical during the second half of the 20th century was attested to by the Tony Award for Lifetime Achievement he received in 2006.

That was his 21st Tony, a number far surpassing that of anyone else in multiple categories. His count began with the 1955 best musical, The Pajama Game, and it reached 20 in 1995 for his direction of an extravagant revival of Show Boat.

Prince was known, especially in the first decades of his theatre life, as a fiendish workaholic. At one point, in 1960, three shows he produced were appearing on Broadway at the same time. He was known, too, for his collaborations with a murderer's row of creative talents, among them choreographers Bob Fosse, Jerome Robbins and Susan Stroman, and composers Leonard Bernstein, John Kander, Stephen Sondheim and Andrew Lloyd Webber.

Sondheim was Prince's most frequent confederate and Webber his most profit-generating, with their work together on Evita, about the opportunistic Argentine populist Eva Peron, and on The Phantom Of The Opera, which Prince directed in London and on Broadway.

His productions were often large in every sense, their emotional resonance heightened by grandiose or otherwise audacious performances (Patti LuPone in Evita, Elaine Stritch in Sondheim's Company) and dazzling, opulent design. Think of the swooping chandelier in Phantom or the Rube Goldberg-esque human-flesh-to-meat-pie mechanism in Sweeney Todd.

"The two things that characterise him most are energy and impatience," Sondheim said in an interview for this obituary in 2016.

He added: "A visual imagination is, if not his greatest strength, then one of them. He sees things visually first and he knows what a show looks like in his head before he takes it on."

Cabaret, written by Kander and Fred Ebb and the first of Prince's directorial efforts to be a hit, was among the first of the so-called concept musicals - shows organised around ideas rather than the telling of a pure story.

It was a herald for a new era in the musical and a new strain in Prince's work, one that became especially evident in his shows with Sondheim, which explored darker, more harrowing elements of the human experience than had generally been portrayed on the musical stage.

Prince and Sondheim, whose mentor was Hammerstein, met in 1949 at the Broadway opening of the Rodgers and Hammerstein musical South Pacific, and their friendship and aspirations ran parallel throughout the 1950s.

The relationship between the two men became a professional one with West Side Story (1957), the now-famous urban adaptation of Romeo And Juliet. At the time, Sondheim was still a young Broadway lyricist working with venerable partners - Bernstein, book writer Arthur Laurents and director Robbins - when he called his friend Prince to complain that the show was in trouble.

Prince and fellow producer Robert Griffith took over the show, which ended up as a striking departure from the conventional book musicals of the day, with its adventurous, modern score and the use of choreography (by Robbins) to propel the narrative.

A harbinger of later developments in the stage musical, West Side Story was a landmark Broadway production, although it won only two Tony Awards, one for Robbins' choreography and the other for Oliver Smith's scenic design.

Prince was born Harold Smith Jr in Manhattan on Jan 30, 1928, to Harold Sr and Blanche (Stern) Smith. His parents divorced and, by the early 1930s, his mother had remarried to Milton Prince, a stockbroker.

In a 1989 biography by Carol Ilson, Harold Prince: A Director's Journey, Prince is quoted as saying that he had never liked his father and that they had not seen each other much, although his father had had a long life. Even so, into the early part of his career, he was known as Harold Smith Prince.

Prince married Judy Chaplin, daughter of composer and lyricist Saul Chaplin, in 1962. In addition to her and to Charles Prince, he is survived by a daughter, Daisy Prince, a theatre director; and three grandchildren.

Prince's first attempt at directing, A Family Affair, a 1962 musical about squabbles over wedding plans, was short-lived. Then came A Funny Thing Happened On The Way To The Forum, a show that Prince produced reluctantly but that was famously saved from oblivion by a new opening number written by Sondheim, Comedy Tonight.

"One quality Hal has is refusing to accept defeat," Sondheim said in the 2016 interview. "It wasn't even that he loved the show that much, but once he was there, it was his baby and he fought for it."

Prince wore his dual hat for the first time in 1963, producing and directing She Loves Me, a romantic comedy based on a Hungarian play that became a 1940 Hollywood film, The Shop Around The Corner.

His next project was Fiddler On The Roof, based on stories by Sholom Aleichem. Produced by Prince, directed and choreographed by Robbins, with music by Bock and Harnick and a book by Joseph Stein, it won nine Tonys and ran for nearly eight years - more than 3,200 performances - the longest run in Broadway history at the time.

Prince was given a Kennedy Center Honors award in 1994 and a National Medal of Arts in 2000. Perhaps the tribute he most coveted, however, ended in disappointment.

An elaborate musical retrospective of his career, Prince Of Broadway, directed by Prince himself along with Stroman, was presented in Japan in 2015. It opened on Broadway in August 2017, but critics were cool to the production and it closed in just over two months. It was his last Broadway production.

It was not Prince's only brush with musical failure, though perhaps none were as poignant as Merrily We Roll Along. Written by Sondheim, it was criticised for its unpleasant tone and Prince's decision to have youthful actors play the roles throughout, even at the start, when the characters are older. It closed after just 16 performances in 1981.

Sondheim and Prince never worked together on Broadway again, although more than 20 years later, they collaborated on another troublesome musical - its various titles included Wise Guys, Bounce and Road Show - that never made it to Broadway.

Sondheim denied that there had been a falling out. He said: "We were both bitter about the experience and there was a lot of Broadway b***hery, but the show failed because people didn't like it."

Then he added: "If there's a burning plane, I want Hal to be the pilot. He's just great faced with difficulties and he's a terrific leader. I watched him after Pacific Overtures had been massacred by critics. And he had to address the cast, give them courage, even though he was hurting just as much. I thought, 'This is a captain'"

NYTIMES