(Hilary Scott / Courtesy Boston Symphony Orchestra)

Four anniversaries, a sensational opera premiere and a missing conductor distinguished the Berkshires' classical-music season in 2013.

It was also a season of conservative programming as presenters strove to hold on to existing audiences and attract young ones through ever more elaborate marketing. We'll get to that trend in a moment. First:

The major composer bicentennials were celebrated at Tanglewood with greatest hits -- Verdi's Requiem and Act III of Wagner's "Walküre." It was with the Verdi that Andris Nelsons was to have made his first appearance as the Boston Symphony Orchestra's recently anointed music director.

That never happened, of course. Nelsons remained at home in Bayreuth, Germany, with a concussion, and the little-known Carlo Montanaro, recruited as a late replacement, led a rushed, hectic performance. Nelsons' coronation scene had to await an autumn program in Boston.

Disappointment all around.

The Latvian Nelsons remains pretty much an unknown quantity at Tanglewood. His one appearance, as a guest in 2012, suggested a dynamo on the podium -- an impression confirmed by the fall concert in Boston. He is due for two Tanglewood weeks in 2014, which should tell more.

The monumental "Walküre" act, on the other hand, was masterfully conducted by Lothar Koenigs, with Bryn Terfel as a deeply conflicted Wotan. Perhaps in a sign of the times, the Shed was only half full for one of the BSO's most far-reaching and powerful offerings.

Britten's centenary was marked with a series of outstanding events at the Tanglewood Music Center, including a semi-danced Mark Morris staging of the opera "Curlew River." The Cantilena Chamber Choir appended a program of choral music in the fall.

Britten's status as a 20th-century master needed no confirmation, but these programs sounded an extra hurrah.

Everybody including the BSO, it seemed, was performing Stravinsky's "Rite of Spring" for the centenary of its riot-wracked world premiere in Paris. The Berkshire Symphony, with assistance from Williams College faculty and students, went everybody one better by staging the riot along with the ballet score, and appending a demo performance of new choreography.

The year's most momentous event was the American premiere of George Benjamin's opera "Written on Skin," performed by TMC students. These 95 minutes of music, linking past and present, rivaled Strauss' "Salome" in combined shock value and musical subtlety. The performance, following a series in major European cities, was a coup for the Tanglewood school and an overwhelming experience.

The Berkshire audience for classical music and opera continues to be primarily in the 50-and-up age bracket, including many retirees and second-homers. (For further evidence, see the Mahaiwe audience for Met simulcasts.)

In mainstream concerts both summer and winter, there were new or adventurous works to be heard, "Written on Skin" certainly among them. But the demographics contributed to emphasis on standard repertoire, leaving the contemporary field primarily to Tanglewood's new-music festival and Mass MoCA's offerings. At Tanglewood, star power, as always, also figured prominently in the BSO's offerings.

Here's the paradox:

The Shed went half empty for "Walküre," yet one of the largest audiences of the season went wild for a wayward performance of Beethoven's Piano Concerto No. 1 by Lang Lang, who reportedly took it upon himself to play a solo encore, thereby keeping the orchestra onstage into overtime.

Is something wrong with this picture?

For all that, Tanglewood had a good attendance season, thanks in part to good weather. Credit also goes to populist programming, including five Pops concerts, a BSO-accompanied screening of "West Side Story" and pop-oriented fare before and after the main BSO season. "The Wizard of Oz" will get film-plus-Pops treatment next summer.

Other outstanding 2013 programs? It's hard to choose but among programs I heard, a few stand out.

Paul Lewis' recital of Schubert's last three piano sonatas at Tanglewood glimpsed a transcendent world of mystery and beauty. Also at Tanglewood, Christoph von Dohnányi led a tremendous Brahms Fourth.

The Boston Early Music Festival's biennial opera productions at the Mahaiwe scored another vocal and dramatic spectacle with Handel's first opera, "Almira." Aston Magna built an intriguing program around the chalumeau, a predecessor of the clarinet.

In chamber music, the trio of violinist Philip Setzer, cellist David Finckel and pianist Wu Han was outstanding at South Mountain. The Berkshire Bach Society presented an impressive Berkshire debut of the St. Luke's Chamber Ensemble from New York.

In Williamstown, the Clark Art Institute showcased a fine ensemble under the rubric of Performing Artists in Residence. The mother-son duo of violinist Miriam Fried and pianist Jonathan Biss sent sparks flying at Williams College.

The Met's opera simulcasts remained popular at the Mahaiwe, Clark and Beacon Cinema. They also continued to prove that, valuable as they are, they are only a movie-like substitute for live music. For real opera, you had to hear Tanglewood's gripping "Written on Skin" and "Walküre."