Nikolaus Harnoncourt was one of the most influential conductors of the 20th century, a pioneer who redefined how we listen to music. A cellist by training, he first revolutionised Baroque performance with his own Concentus musicus Wien, before seeking an ensemble that could bring the same spirit of discovery to the Classical and Romantic repertoire. His encounter in 1986 with the young Chamber Orchestra of Europe was the beginning of a unique artistic partnership. Harnoncourt demanded extremes of colour, tension and risk, challenging the musicians to abandon routine and rediscover the radical force of Mozart, Beethoven, Schubert or Schumann. What began as a trial evolved into decades of groundbreaking concerts, operas and recordings, from revelatory Beethoven cycles to Schumann and even Gershwin. Their collaboration not only transformed the orchestra but also left a lasting mark on performance history, setting interpretative standards that continue to inspire musicians worldwide.