For more than 45 years, Pierre Boulez played an important role in the artistic life and legacy of the Chicago Symphony Orchestra. The conductor-composer and classical-music visionary, who died Jan. 5, 2016, in Baden-Baden, Germany, at the age of 90, was universally regarded the leading figure in his field during the last half of the 20th century.

With all his brilliance, many knew him best as a friend. In a tribute to Maestro Boulez, CSO annotator Phillip Huscher wrote: “As the CSO’s official conductor emeritus, unofficial éminence grise, and above all, beloved member of the family, his work with our musicians and his presence in our city encompassed so much more than any conventional title could suggest.”

So it was only fitting that CSO members made a side trip to pay their respects to the maestro ahead of their concert in his hometown. In a statement released after the maestro’s death, French president François Hollande crystallized the essence of Boulez: “He never ceased to think about subjects in relation to one another; he made painting, poetry, architecture, cinema and music communicate with each other, always in the service of a more humane society.”