LENOX — “New music without any sense of apology.”

That’s how the patron Paul Fromm (1906-87) described the contemporary music haven he helped build at Tanglewood.

With so much history now in the air at the BSO’s summer home, and with the Tanglewood Music Center’s renowned Festival of Contemporary Music having just ended on Monday night, it seems fitting to take a moment for Fromm, that remarkable German émigré, wine importer, and musical idealist in the grand Koussevitzkian mold.

“I have a profound longing,” he once declared at Tanglewood, “to live in a community where the significance of music is recognized as an integral part of our cultural and intellectual life, where the sustenance and development of the music of our time is a deeply felt responsibility.”

Fromm, who also will be the focus of an exhibition opening this winter at Harvard’s Loeb Music Library, was troubled by the peripheral status of composers in his adoptive home, and by what he saw as the peculiarly American insistence “that music make its way in the marketplace as if it were a commodity of some kind.” Over many years he lavished his generosity on, among many other institutions, the Berkshire Music Center (TMC’s predecessor), writing to Aaron Copland in the early days of the Fromm Foundation: “You can plan boldly since we do not intend to sponsor contemporary music in economy size over the thrift counter.” For his part, Copland called Fromm “our own Prince Esterházy.”

Fromm’s support was crucial to the establishment, in 1964, of the Festival of Contemporary Music, those utopian few days every summer when the “apologetic” approach takes a holiday, and when adventurous listeners from far and wide stream onto a small corner of these bucolic grounds to revel in the sounds of the new.

This summer’s programs (several were previously reviewed in the Globe) dreamed up by festival director Oliver Knussen, aimed for depth over stylistic breadth, but still heeded Fromm’s original call for ambitious thinking.

HILARY SCOTT

For the Festival of Contemporary Music, Gunther Schuller led the TMC orchestra in an all-Ives program.

Sunday evening’s concert began with an arresting orchestral work, “Inverno In-ver,” by the largely forgotten Italian composer Niccolo Castiglioni (1932-96). Knussen, who has championed his music, conducted a small orchestra of TMC fellows in this wintry procession of movements (here called “musical poems”) with titles such as “Ice Flowers,” “The Frost,” and “The Frozen Lake.” Castiglioni was clearly a master of timbral detail, and this music builds up coolly glittering sonorities from strings in their highest registers, pointed percussion, and daubs of woodwind color. Sunday’s exacting Knussen-led performance suggested a kind of impeccable modernist nature painting. Imagine Vivaldi at Darmstadt.

But the Castiglioni was only a prelude to the night’s main offering, the East Coast premiere of Knussen’s opera “Higglety Pigglety Pop!,” with a libretto by Maurice Sendak based on his lovably peculiar children’s book. Sendak’s classic tale unfolds as a kind of whimsical, pint-size bildungsroman about a dog named Jennie who leaves her comfortable home to seek adventure, driven by her belief “that there must be more to life than having everything.”

Sendak’s dry wit shines through the libretto, too. (When a houseplant questions Jennie’s wanderlust, she responds by eating the plant, leaf by leaf, as its singing is reduced to monosyllables.) In a program note, Sendak, who died in May at 83, calls “Higglety” his favorite among all his works, and describes it as a requiem to his own dog but also as “my quiet testament to the artist’s life.” Sunday’s concert performance was dedicated to his memory.

Knussen’s score, deftly led by Stefan Asbury, brims with vibrant and vigorous music, complexity put to the service of fantasy. Vocal duties Sunday were shared by a strong cast of young singers, including Kate Jackman, Ilana Zarankin, Sharon Harms, Zach Finkelstein, Richard Ollarsaba, and Douglas Williams. The performance also benefited from Netia Jones’s striking digital projections of animated Sendak images, often coordinated in real time with the musical performance.

Monday night’s program included a fine orchestral work, “Everyone Sang,” by the impressive young British composer Helen Grime, and George Benjamin’s absorbingly protean “Duet” for piano and orchestra, with soloist Peter Serkin. The evening’s biggest cheers went to Gunther Schuller, whose vivid new “Dreamscape” was reprised, this time led by Knussen. The score reaffirmed the strong impression made at its premiere, with a first movement suggesting a lifetime of musical memories swirling through the unconscious, colliding at odd and irreverent angles; and its “Nocturne,” a kind of dream within a dream, with gleaming clarinet lines flashing up across a dark orchestral landscape. The finale — “Birth — Evolution — Culmination” — as you might expect, concisely covers a lot of ground.

Meanwhile, as the students and new music experts threw their party in Ozawa Hall, the other Tanglewood kept churning, too. Soloists drove much of last weekend’s BSO news, with Yo-Yo Ma diving deeply into Elgar’s Cello Concerto in a rapturously expressive performance on Saturday night. On Friday violinist Pinchas Zukerman led a refreshingly collaborative all-Bach program, with concertmaster Malcolm Lowe, principal oboe John Ferrillo, principal flute Elizabeth Rowe, and harpsichordist John Gibbons each taking solo turns. On Sunday afternoon, under Christoph von Dohnanyi’s baton, the English pianist Paul Lewis made a superb BSO debut in Mozart’s Piano Concerto No. 23, conveying a kind of worldly exuberance and Apollonian refinement in equal measure.

New music made an appearance in the Shed last weekend as well, with Andre Previn’s “Music for Boston,” a BSO commission, given its first performance under the direction of Stéphane Denève, a French conductor who is also likely a contender, at least on some level, for the BSO’s music director post. Unfortunately, Previn’s work, a piece designed to showcase individual sections of the orchestra, does just that, but in the process adds up to little more than a collection of less-inspired moments. Many of them, even though skillfully crafted, left you thinking more about Previn’s debts to the sound worlds of composers past (the spirits of Bartok and Shostakovich loom large here) than about any forceful new statement born of the present. (Denève also reprised the Shostakovich Fifth Symphony he led earlier this season in Symphony Hall, with comparably mixed results.)

After taking in both BSO Shed concerts and Ozawa Hall FCM programs last weekend, I was struck by how far apart the two worlds seemed, a fact only somehow underscored by the dutiful BSO Previn premiere. No other major orchestra in America offers a student-fueled program quite like FCM, with its joyfully, yes, unapologetic marathon celebration of new music. But other forward-thinking ensembles around the country have taken steps to integrate new music more centrally into the orchestra’s primary year-round agenda — by appointing composers-in-residence, and by creating special dedicated new music series that involve the orchestras’ own players, with concerts that take place during the subscription season in smaller venues that do not carry the burden of selling seats by the thousands.

Similar steps are long overdue at the BSO. As the festival Fromm helped build approaches its own 50th anniversary, the most meaningful way to honor the FCM’s legacy would be to narrow the yawning gap that separates these glorious few days in Ozawa Hall from the everyday life of the orchestra.