Being obsessed with the newest trends may seem like a recent phenomenon, an endless cycle in which new talent is swiftly pushed aside as the latest up-and-coming artist emerges, but even in terms of classical music, it goes back several centuries.

Take Mozart for example. He struggled with changing tastes throughout his career: moving from his native Salzburg to Vienna as an adult may have helped him make a clean break from the days when was regarded as a former child prodigy, but he would later complain about the fickleness of Viennese audiences. In terms of peaking early, however, some argue that the very best of Mendelssohn can be found in his String Octet and Overture to A Midsummer Night’s Dream, both written when he was in his teens.

Both composers’ posthumous reputations have had their ups and downs – Schumann’s assessment of the ‘Grecian lightness and grace’ in Mozart’s Symphony No.40 would raise eyebrows today, though this is nothing compared to Wagner’s antisemitic dismissal of Mendelssohn - but their standing is now secure.

Interestingly, the same applies to JS Bach, a composer with whose music Mozart and Mendelssohn alike had memorable encounters at a time when his works were at best considered useful teaching materials.

As the Scottish Chamber Orchestra celebrates the 350th anniversary of his monumental St Matthew Passion (1-2 October) – a retelling of Christ’s final days on Earth, culminating in the crucifixion – how did Bach go from all but forgotten to being celebrated as a founding father of Western classical music?

To be fair, it had all started in his own lifetime. Never one to follow fashions, Bach continued to plough his own furrow long after tastes had moved away from the intricate, often cerebral music he favoured to something that prized simpler, elegant lines and Classical proportions. He came to be better known as an organist than a composer, to the extent that the young Mozart (born a mere 6 years after Bach’s death) was brought up more familiar with music by the next generation of the Bach family. Hearing music by their father while visiting Leipzig in 1789 proved a revelation: “here is something one can learn from!”, he exclaimed, before reportedly sitting on the floor with sheets of Bach scattered all around him, eagerly taking them up one after the other.

If Mendelssohn’s first encounter with the great man don’t sound so wonderfully geeky, that is because his family already revered him as part of their own musical heritage. His great aunt Sarah Levy had been a favourite pupil of Wilhelm Friedrich Bach (JS’ eldest son) and became something of a self-appointed guardian of the Baroque torch in later years. It was her sister Sarah, however, who ignited the spark for Mendelssohn by giving him a score of the St Matthew Passion, possibly as a 15th birthday present. Four years later, in 1829, he would spearhead the its first known performance in perhaps half a century, and the Bach revival really took off.

Not that Baroque music had been entirely forgotten. Handel had remained popular (and a favourite of Beethoven’s), possibly because his music was generally more immediately accessible, even if the musical world wasn’t above reorchestrating it to suit then contemporary tastes. (Mozart himself added a full complement of wind instruments to Messiah, perhaps setting the seal for Eugene Goossens going to town with a percussion section that included cymbals and an anvil, for performances led by Thomas Beecham in the 1950s.)

Mendelssohn’s approach to the St Matthew Passion for his performance in Berlin was similar, though this was more for reasons of practicality. He reorchestrated some of the music, among other things to make up for the oboe d’amore and viola da gamba (both included in Bach’s original score) being to all intents and purposes obsolete. Condensing the work – he cut about a third of the arias – may also have been a pragmatic decision: to this day, a concert promoter might think twice about putting on a performance of an unfamiliar work that lasts over three hours.

Perhaps Mendelssohn should have had greater faith in both his audience and the music. Bach’s reputation suddenly took off, with cultural figures falling over themselves to praise this long-overlooked composer. The centenary of Bach’s death was marked with the foundation of the Bach-Gesellschaft Leipzig (Leipzig Bach Society), and plans were soon underway to publish all his known works. By the time this process was completed in 1899, choirs named after Bach had been set up across the entire German-speaking world as well as in Britain, the latter no doubt aided by Queen Victoria’s enthusiasm for Germanic culture.

As much as Bach’s music was rehabilitated, however, performing Baroque music as its composers would have known it wouldn’t be a concern until the 1950s. Back in the late 19th century, it was felt that a work as vast as the St Matthew Passion deserved to be heard with forces to match. It wasn’t unusual for its performances to require over 400 musicians on stage, also reflecting how much the orchestra had expanded since Bach’s day. By 1913 – only a year after the St Matthew was first performed with no cuts, and still four decades before historically-informed performances even began – George Bernard Shaw (then a music critic) was calling for “a law making it a capital offence to perform an oratorio by Handel with more than 80 performers”.

By and large, composers gave Passions a wide berth in the wake of the St Matthew’s rediscovery. (As it is, the only setting to rival it is Bach’s own St John Passion.) Stainer’s 1887 Crucifixion does buck this trend – albeit only in the English-speaking world – but the first significant Passion of the 20th century is Penderecki’s 1965 setting of the St Luke. As a genre, the Passion would enter the mainstream in the 1970s, when elements of the story were included in the musical Godspell and rock opera Jesus Christ Superstar.

Bach himself has of course long since gained the reputation he deserved all along. Composers from Liszt to Schnittke have been paying musical tribute to him ever since that historic revival of the St Matthew Passion, and his influence on musicians continues to be felt to this day. Bartók and Shostakovich are perhaps foremost among those in the classical sphere, but casting the net wider, Jacques Loussier and Wendy Carlos both come to prominence with pioneering reinterprations of his music, in Play Bach No.1 and Switched-On Bach respectively. In what may be considered the truest sign of pop culture recognition today, he was even the subject of an interactive Google Doodle in 2019.

The word comeback is applied to any number of people whose career has taken off again after a slump, but in the light of how we view Bach today – in no small part thanks to Mendelssohn – we should perhaps hold him up as the benchmark.