Late last month, with the passing of the conductor Kurt Masur at the age of 88, the 20th century in music seemed to slip a bit further into the past.

Audiences of the Boston Symphony Orchestra got to know Masur well from his dozens of visits to Symphony Hall and Tanglewood over the decades. New Yorkers got to know him even better when he served as the New York Philharmonic’s music director from 1991 to 2002.

But Masur’s name will first and foremost remain linked to another ensemble of the oldest tradition: the Leipzig Gewandhaus Orchestra, which he directed for over a quarter century beginning in 1970. This made him one of the last major maestros to have built his career behind the Iron Curtain.

Doing so obviously entailed its own set of restrictions and challenges, but it also conferred the benefit of an unrushed professional development. Masur did not make his US debut until his late 40s, and first led the BSO in 1980 at the age of 52. It further meant a certain isolation from the homogenizing stylistic winds blowing through the international orchestral world. Masur was the proud custodian of a specific older Leipzig sound, and of a history that stretched back to the mid-18th century. As director, or Kapellmeister, Masur held a title once held by Felix Mendelssohn (and soon to be assumed by Andris Nelsons). During his tenure, Masur restored this depleted orchestra to its full splendor, and even presided over the building of a new concert hall to succeed the Gewandhaus that was damaged by Allied bombing during the Second World War.

Working in East Germany also gave Masur an intuitive grasp of an expanded social and civic potential for classical music itself. He understood well that in a place where other freedoms were curtailed, the arts could become a kind of alternative currency of the spirit and the carrier of a moral charge. In 1989, Masur’s de facto role as a cultural-cum-political leader in Leipzig came to its fullest expression in the tense weeks just prior to the fall of the Communist regime. At one key juncture, as citizens and state forces were heading for a potentially deadly clash, Masur stepped forward and insisted on calm dialogue. He invited all parties into the Gewandhaus, and broadcast a speech throughout the city urging de-escalation and peace. His actions, in retrospect, were seen as having prevented needless bloodshed.

After the fall of the Berlin Wall, Masur, at the height of his prestige in Germany, was pressed by some toward a career in national politics. He declined. Moral leadership was needed, he knew, but music was his medium of choice, in part for its ability to reach the deepest levels of the self. “Music makes you aware of who you are,’’ he once said in a television interview, “[and] that life and death [are] connected to each other.’’

At the New York Philharmonic, Masur brought not only these values but also an infusion of Germanic rectitude and heavy-handed discipline. Players chafed at the imposition. “We had to fight a lot in my years,’’ Masur told me in a 2004 interview. “In the beginning, my intensity disturbed them.’’ But the orchestra’s sound sure enough was transformed eventually, and Masur deserves credit for its restoration.

In New York during the 1990s, opportunities for the kind of civic leadership Masur had exerted in Leipzig were few, but he held unabashedly to his lofty ideals. As the turn of the 21st century approached and countless worried about the cyber-health of Y2K-exposed computers, Masur had other things on his mind. He commissioned a group of composers — among them Thomas Adès, Hans Werner Henze, Giya Kancheli, Kaija Saariaho, and John Corigliano — to write new works for a project titled “Messages for the Millennium.’’ In Masur’s world, composers held a privileged position of insight, and as he saw it, we needed their dispatches more than ever.

It may have been easy to dismiss Masur’s earnest musical idealism, but it was more difficult to discount its effects in practice. After the attacks of September 11, he walked on stage before a hall full of nerve-shattered listeners, this one included, and led the New York Philharmonic and the assembled vocal forces in a remarkable performance of Brahms’s “German Requiem.’’ What made it memorable was the sense of occasion Masur convened. In his hands, this was not just a poignant performance in the wake of tragedy; it was a proud defense of humanistic values and community.

Tanglewood audiences may also recall Masur’s final appearance there, when illness prevented him from taking on a full program but he nonetheless insisted on performing Mozart’s Symphony No. 36. His range of physical movement was extremely limited, but by that point, he didn’t need much. His personality seemed to infuse the orchestra, and the BSO gave a warmly drawn, dignified, and thoroughly Masurian performance. The remaining portion of his program was taken up by his son, Ken-David Masur, who is now a BSO assistant conductor.

In an era when orchestras in search of elusive new audiences take to nightclubs, invest in shiny apps, and invite pop stars to perform next to the podium, there is something worth honoring in Masur’s bygone brand of artistic idealism and integrity. He made those qualities vital by sheer dint of his own specific commitment and the history through which he lived, bearing fruits that were open to all.

“I want [music] to be touching,’’ he once said. “I want it to give people a feeling in the concert hall of being at home, being at home with themselves, with their ideas, with their soul. They discover that their life also makes sense while they are listening to music.’’

Jeremy Eichler can be reached at jeichler@globe.com.