Three decades ago, a group of inquisitive London musicians took a long hard look at that curious institution we call the Orchestra, and decided to start again from scratch. They began by throwing out the rulebook. Put a single conductor in charge? No way. Specialize in repertoire of a particular era? Too restricting. Perfect a work and then move on? Too lazy. The Orchestra of the Age of Enlightenment was born.

And as this distinctive ensemble playing on period-specific instruments began to get a foothold, it made a promise to itself. It vowed to keep questioning, adapting and inventing as long as it lived. Those original instruments became just one element of its quest for authenticity. Baroque and Classical music became just one strand of its repertoire. Every time the musical establishment thought it had a handle on what the OAE was all about, the ensemble pulled out another shocker: a Symphonie fantastique here, some conductor-less Bach there. All the while, the Orchestra’s players called the shots.

At first it felt like a minor miracle. Ideas and talent were plentiful; money wasn’t. Somehow, the OAE survived to a year. Then to two. Then to five. It began to make benchmark recordings and attract the finest conductors. It became the toast of the European touring circuit. It bagged distinguished residencies at the Southbank Centre and Glyndebourne Festival Opera. It began, before long, to thrive.

And then came the real challenge. Eccentric idealists the ensemble’s musicians were branded. And that they were determined to remain. In the face of the music industry’s big guns, the OAE kept its head. It got organized but remained experimentalist. It sustained its founding drive but welcomed new talent.

It kept on exploring performance formats, rehearsal approaches and musical techniques. It searched for the right repertoire, instruments and approaches with even greater resolve. It kept true to its founding vow. In some small way, the OAE changed the classical music world too. It challenged those distinguished partner organizations and brought the very best from them, too. Symphony and opera orchestras began to ask it for advice. Existing period instrument groups started to vary their conductors and repertoire. New ones popped up all over Europe and America.

And so the story continues, with ever more momentum and vision. The OAE’s series of nocturnal Night Shift performances have redefined concert parameters. Its home at London’s Kings Place has fostered further diversity of planning and music-making. Great performances now become recordings on the Orchestra’s in-house CD label, OAE Released. The ensemble has formed the bedrock for some of Glyndebourne’s most groundbreaking recent productions. It travels as much abroad as to the UK regions: New York and Amsterdam court it, Birmingham and Bristol cherish it.

Remarkable people are behind it. Simon Rattle, the young conductor in whom the OAE placed so much of its initial trust, still cleaves to the ensemble. Iván Fischer, the visionary who punted some of his most individual musical ideas on the young orchestra, continues to challenge it. Mark Elder still mines for luminosity, shade and line. Vladimir Jurowski, the podium technician with an insatiable appetite for creative renewal, has drawn from it some of the most revelatory noises of recent years. John Butt, the intellectual powerhouse, pushes for well-researched period performance excellence. All five share the title Principal Artist.

Of the instrumentalists, many remain from those brave first days; many have come since. All seem as eager and hungry as ever. They’re offered ever greater respect, but continue only to question themselves. Because still, they pride themselves on sitting ever so slightly outside the box. They wouldn’t want it any other way.