Image source, Getty Images

The American composer and songwriter Stephen Sondheim has died at his home in Connecticut aged 91, according to the New York Times. He was a titan of musical theatre who turned the unlikeliest of subjects into entertainment landmarks.

From Sweeney Todd and the president killers of Assassins to the fairy tale-based Into the Woods, his works boasted an audacity, complexity and linguistic dexterity that few of his peers could rival.

Born in New York in March 1930, the composer and lyricist saw his first Broadway musical at the age of nine.

The following year he met Oscar Hammerstein II, of The King and I and Oklahoma! fame, who became his mentor as he made his first forays into musical theatre.

After some adolescent experiments with the form, he was commissioned to turn Front Porch in Flatbush, a play by twin brothers Julius and Philip Epstein, into a musical.

The resulting piece, called Saturday Night, did not open on Broadway in 1954 as planned, following the death of its producer, Lemuel Ayers. Indeed, it would be 43 years before it received its professional premiere in London.

Image source, Getty ImagesImage caption, Stephen Sondheim wrote lyrics for Leonard Bernstein's West Side Story

Sondheim's big break instead came through an invitation to pen lyrics for West Side Story, Leonard Bernstein's contemporary retelling of Shakespeare's Romeo and Juliet.

In 2012, producer Hal Prince recalled the first time he heard the score for the show.

"It was a Sunday evening at Lenny Bernstein's apartment with Lenny playing the piano very loudly because he was nervous," he told the BBC. "Steve sang the words. By the time they'd finished, I knew we were producing. We raised the money in 24 hours."

West Side Story opened on Broadway in 1957 and ran for more than 700 performances. A 1961 film version won 10 Oscars.

Image source, Getty ImagesImage caption, West Side Story was a successful musical stage show and film, which featured Rita Moreno

Yet Sondheim was dissatisfied with his contribution and later described his lyrics as "embarrassing".

"It's very hard for me to listen to some of those songs," he told ABC News in 2010.

"Bernstein wanted the songs to be heavy, what he called 'poetic', and my idea of poetry and his idea of poetry are polar opposites."

Sondheim had further success as a lyricist with the 1959 musical Gypsy, about striptease artist Gypsy Rose Lee and her domineering mother, Rose.

That was followed in 1962 by A Funny Thing Happened on the Way to the Forum, an adaptation of farces by ancient Roman playwright Plautus, for which he wrote both music and lyrics.

The show won a Tony for best musical and was later filmed with original lead, Zero Mostel, reprising his role as wily slave Pseudolus.

Image source, Getty ImagesImage caption, Sondheim's work was celebrated in a revue, Side by Side by Sondheim, which was itself nominated for several awards

Sondheim's next shows – Anyone Can Whistle, from 1964, and Do I Hear A Waltz? the following year – were not successes.

Neither was a reunion with Bernstein and West Side Story director Jerome Robbins on a project that was eventually abandoned.

Over the following decade, though, he worked with Prince on a series of acclaimed shows that are now regarded as modern masterpieces.

Company (1970) told of a single New Yorker, called Bobby, whose married friends teach him the value of commitment.

The original production was nominated for 14 Tonys and won six, with Sondheim receiving one apiece for his music and lyrics.

A 2018 revival in London made the lead character female – with Sondheim’s blessing.

Follies (1971) imagined the reunion of a group of ageing vaudevillians who relive their youth in a Broadway theatre scheduled for demolition.

Its score included the song Losing My Mind, which became a UK top-10 single when covered by Liza Minnelli in 1989.

A Little Night Music (1973) saw Sondheim nimbly adapt the 1955 Ingmar Bergman film Smiles of a Summer Night into a sprightly operetta.

Image source, Getty ImagesImage caption, Elizabeth Taylor sang in the film version of A Little Night Music

The score, written primarily in waltz time, included the poignant ballad Send in the Clowns, arguably his best-known song. A Little Night Music later became a film, starring Elizabeth Taylor.

The composer's golden decade concluded with Sweeney Todd: The Demon Barber of Fleet Street (1979), a bold, baroque and very bloody account of the throat-slitting barber's nefarious adventures.

The "musical thriller" was filmed in 2007 by director Tim Burton, with Johnny Depp as Todd and Helena Bonham Carter as his pie-making accomplice, Mrs Lovett.

In contrast, Merrily We Roll Along (1981) was a disappointment, opening to sniffy reviews and closing after just 16 performances.

But the show, which follows two decades in the lives of a group of friends in reverse chronological order, has been more warmly appraised in recent years.

Image source, Getty ImagesImage caption, Tim Burton made a film version of Sweeney Todd: The Demon Barber of Fleet Street

In 2019, director Richard Linklater began work on a film version, to be assembled in stages, in real time, over 20 years.

Sunday in the Park with George (1984) took the painting of Georges Seurat's A Sunday Afternoon on the Island of La Grande Jatte 100 years earlier as the cue for a lyrical contemplation on "the art of making art".

The musical won Sondheim and librettist James Lapine the Pulitzer Prize for Drama.

Into the Woods (1987) combined such Grimms' fairy tale characters as Cinderella, Rapunzel and Little Red Riding Hood within a single narrative.

It, too, was filmed, in 2014, with an all-star cast, headed by Meryl Streep.

Image source, Getty ImagesImage caption, Sondheim's Sunday in the Park with George was inspired by French painter Georges Seurat

Assassins (1990) used a similar conceit, combining John Wilkes Booth, Lee Harvey Oswald and others together in a dark meditation on presidential assassination attempts.

The following year Sondheim won an Oscar for Sooner or Later, sung by Madonna in the film Dick Tracy.

In Sondheim's later years he produced fewer musicals directly for the stage.

But he continued to create regardless, producing the non-musical play Getting Away with Murder (1996) and two volumes of annotated lyrics – Finishing the Hat (2010) and Look, I Made a Hat (2011).

In 2010, the year he turned 80, a Broadway theatre was renamed in his honour.

Ten years later, he received the same accolade in London when the Queen's Theatre in Shaftesbury Avenue was rechristened the Sondheim.

Image source, Getty ImagesImage caption, Barack Obama awarded Stephen Sondheim the Presidential Medal of Freedom in 2015

Sondheim's many other honours include a special Tony in 2008, a special Olivier in 2011, and the Presidential Medal of Freedom in 2015.

He is survived by his husband, Jeffrey Scott Romley, who is almost 50 years his junior, whom he married in 2017.

"You have to work on something that makes you uncertain – something that makes you doubt yourself," Sondheim said in 2017.

"If you know where you're going, you've gone, as the poet says. And that's death."