Always drawn to unusual and varied subjects – a psychopathic barber, a 19th-century French painter, a bachelor scared of commitment, a reunion of retired chorus girls, to name just a few – Sondheim adapted his musical language accordingly. He reinforced the Viennese tone of A Little Night Music (1973), for example, by writing every number in 3/4 time; and in Sunday in the Park with George (1984), he transformed pointillism in art into pointillism in music. As David Patrick Stearns (DPS) wrote for Gramophone (8/88): ‘Sondheim responds to the dramatic material and then lets the world decide after the Broadway run whether the show belongs somewhere loftier – or at least further “uptown”.’ Like his predecessors – especially Leonard Bernstein, with whom he collaborated as lyricist on West Side Story – Sondheim’s style couldn’t be neatly pigeon-holed, which – for someone more focused on reflecting the human condition in all its guises than creating a smash-hit musical where ‘everything turns out terrific in the end’ – suited him just fine: ‘I’m interested in sung language, storytelling,’ he said. ‘That’s what I like.’

Born in Manhattan, Sondheim studied piano and organ from the age of seven (he’d been playing by ear from the age of four). One significant early musical discovery was Ravel; he later credited the composer for influencing nearly all popular and show music. Through his mother, he met the lyricist Oscar Hammerstein, who became a sort of surrogate father to him (his biological father had divorced his mother when he was 10), as well as a mentor in writing for musical theatre. Sondheim studied music and maths in Massachusetts, and then privately with the composer Milton Babbitt. He wrote music for revues with Richard Rodgers’s daughter Mary, and, in 1956, the incidental music for the Broadway show The Girls of Summer. Later that same year, he was asked to write the lyrics for West Side Story. Bernstein was initially a co-lyricist, but he later withdrew his name from the credits to acknowledge Sondheim’s significant contribution, which (despite Sondheim’s later self-denigration regarding the work) clearly showed an ability to develop both character and plot through lyrics.

Gypsy (1959) was Sondheim’s next project, but he was replaced as composer by the more experienced Jules Styne and ultimately provided only the lyrics (including the unforgettable ‘Everything’s Coming Up Roses’). His first success as both composer and lyricist was A Funny Thing Happened on the Way to the Forum (1962), followed by Anyone Can Whistle (1964), a commercial flop which nevertheless became a cult favourite. Company (1970), however, ran on Broadway for a year and has been revived multiple times – including by Marianne Elliott for a groundbreaking gender-reversed version in the West End which, as Edward Seckerson wrote in his review of the cast recording (6/19), ‘underlines just how receptive this and other of Sondheim’s masterpieces are to our changing times’.

Other successes included Follies (1971) and Sweeney Todd (1979), the latter a homage to London, his second home, whose score owed much to film composer Bernard Herrmann and which was in fact adapted for cinema by Tim Burton in 2007. David McVicar staged it for Opera North in 2002, and a decade later it returned to the London stage in Jonathan Kent’s production; in 2015 it was performed (with Bryn Terfel as Sweeney Todd and Emma Thompson as Mrs Lovett) at English National Opera.

Into the Woods (1987), which was also adapted for film, was another score that broke new ground. Describing the music as ‘Sondheim’s most intricate and refined so far,’ DPS singled out the work’s ‘fluid integration of speech and song’, describing it as a style ‘not unlike Richard Strauss’s Intermezzo’.

In 2006, Sondheim announced that, as a result of his advancing years, there were ‘no more ideas’. Yet less than a week before his death, he was discussing a ‘surreal’ new musical with his friend, the impresario Cameron Mackintosh. Like so many of Sondheim’s on-stage characters, it’s hard for us not to regret what might have been. At the same time, everyone who encountered his work can feel immensely grateful for all he achieved which will, both on stage and via recordings, continue to endure.