This is one of those days I always knew would come – at least for the last five years or so – and now I am very sorry it’s here. For the conductor Michael Tilson Thomas has died.

In my memory, Tilson Thomas will always be the effusive, boyish protégé of Leonard Bernstein. There are many, I’m sure, who during those early years predicted he would inherit Bernstein’s mantle as the most recognized and beloved American conductor. Alas, it did not come to pass. It’s not that he wasn’t recognized and beloved, but there could be only one Leonard Bernstein. Still, MTT had a great career and a rewarding life. You can’t fault excellence for not attaining superstardom.

At one time or another, he held positions as music director of the Buffalo Philharmonic, chief conductor of the London Symphony Orchestra, founder and artistic director of the New World Symphony (an ensemble made up of gifted young musicians), and music director of the San Francisco Symphony. He also enjoyed a fruitful relationship with the Boston Symphony Orchestra, of which he was once assistant conductor and with which he made some classic recordings.

Ove the course of his career, Tilson Thomas amassed a cabinet full of Grammys, a Peabody Award, a National Medal of Arts, and a Kennedy Center Honor. Like Bernstein, he was also a composer. A few of his works reflected his Jewish heritage and honored his grandparents’ experience in the Yiddish theater. (He was the grandson of Boris and Bessie Thomashefsky.)

There’s plenty in his discography that’s given me great pleasure over the years: recordings of the symphonies of Charles Ives; orchestral works of Aaron Copland and Igor Stravinsky; a colorful selection of “Bachianas Brasileiras” by Heitor Villa-Lobos; a fascinating curio, “The American Flag,” by Antonín Dvořák; an album of the late choral works by Beethoven (including “Calm Sea and Prosperous Voyage”) that I acquired on vinyl at my local record store in high school; of course his Gershwin records, especially the one with “Rhapsody in Blue” in its original version; and a knock-out disc of American orchestral works, including Walter Piston’s Symphony No. 2, Ives’ “Three Places in New England,” and that prickly masterpiece, Carl Ruggles’ “Sun-Treader.”

MTT recorded the complete works of Ruggles, a cantankerous, problematic composer, who wrote music of uncompromising integrity and dissonance. These were released on a two-LP set on CBS Masterworks. It must have sold about five copies, because the label never bothered to reissue it on compact disc, so that it became a kind of Holy Grail among collectors. It finally reappeared on the independent label Other Minds, 37 years later, in 2017! It would have been nice had they retained the design of the original album, but some of the elements were the same. Significantly, they were able to hang on to the program notes, which were supplemented by photos and an essay by Lou Harrison.

Tilson Thomas conducted the first concert I ever saw with the Philadelphia Orchestra at the Mann Music Center in the summer of 1984, when he was joined by André Watts, the soloist in Rachmaninoff’s Piano Concerto No. 2, and after intermission led the ensemble in Bartók’s Concerto for Orchestra – with a thunderstorm looming, no less. Why they didn’t clear the lawn, I have no idea. You were just expected to pull your shirt over your head or run for cover in those days.

The last time I saw him was in Philadelphia in 2008, this time indoors at the Kimmel Center for the Performing Arts, when he was joined by Paul Jacobs for Aaron Copland’s Organ Symphony and then, on the concert’s second half, he conducted Mahler’s Symphony No. 5.

As is so often the case, we tend to take what’s available to us for granted. So it was like a splash of ice water, when five years ago, Tilson Thomas was diagnosed with glioblastoma, an aggressive form of brain cancer. Although he scaled back his activities for treatment and to husband his resources, he continued to perform, and during the period, a sort of sustained victory lap, he was received by audiences everywhere with notable warmth.

His husband, Joshua Robison, died only two months ago. The two met in junior high school and were together for 50 years.

Tilson Thomas is one of those figures I will always remember in the summer of his youth. I recollect watching him play Copland’s Piano Variations on a PBS television documentary about the composer, broadcast over 40 years ago now, and his commentary about the piece, which he compared to a skyscraper in sound. I can’t get over how quickly time passes.

Michael Tilson Thomas was 81 years-old. R.I.P.