It’s not often that a band reaches its 45th anniversary. Keeping any musical venture alive for four-and-a-half decades is impressive in itself, let alone celebrating the occasion with a sold-out 14-night residency at New York’s Beacon Theatre. There’s also the fact that the 3-hour shows during said Beacon run feature set lists fresh with deep cuts and bust-outs, plus rosters of guests from myriad spots on the musical spectrum. When it comes to hitting milestone achievements, the Allman Brothers score serious bonus points. (And this isn’t a one-off: they’ve been selling out their annual March Beacon run since 1989.)

Alas, it seems that 2014 is most likely the Allman Brothers’ last year together. In January, guitarists Warren Haynes and Derek Trucks and longtime bassist Oteil Burbridge–who joined in 1989, 1996, and 1997 respectively–announced that they will depart the band at the end of this year. The Allman Brothers as a unit then officially announced that they will no longer tour after 2014. Despite the fact that all signs point to a breakup, some fans find promise in the evidence that this year’s Beacon residency hasn’t been advertised as the final one. Wishful thinkers hope that maybe–just maybe–the band won’t define two weeks in one city every March as “touring.”

Catch one show at the Beacon and you’ll see why plenty of fans aren’t ready to accept that the Allman Brothers might soon be done for good. Logically, a band’s 45th anniversary sounds like an appropriate time for it retire. But when the lights went out in the lavish Upper West Side theatre on March 19, that logic stopped making sense. America’s most tenacious multi-generational musical legacy walked on stage to roaring applause. The opening riff of the classic “Statesboro Blues” instantly brought the audience to its feet, and Gregg Allman–seated at the organ with his signature long white-blonde hair illuminated under the spotlight–filled the room with his familiar Southern crooning.

The defining trait of the Allman Brothers’ current iteration is its mix of older and comparatively younger talent. Allman and the other founding members, drummers Butch Trucks and Jaimoe, lend themselves to a mythic kind of presence that tethers the present-day band to its storied history of tragedies, triumphs, and personal hardships. At the same time, their bandmates weave innovative, forward-thinking musicianship into the Brothers’ oeuvre. So when Warren Haynes stepped up to the mic on this particular night to belt out Freddie King’s “Woman Across the River,” the song felt like an immensely gratifying blend of past and present–just as it did when Allman and Haynes later traded verses on the feel-good tune “Soulshine.” Likewise when Derek Trucks closed out the first set wailing on a chillingly beautiful slide guitar solo during the Eat a Peach favorite “Ain’t Wastin’ Time No More.”

The band’s emphasis on its bonds of family and friendship is a hallmark of the annual Beacon residency. Throughout the decades, the untimely deaths of Duane Allman, Berry Oakley, Lamar Williams, and Allen Woody wounded the group–and the Brothers always make an effort to tie their live performances to past members’ contributions. At this show, Williams’ son Lamar Jr. sang “Midnight Rider” with Allman at the beginning of the second set. One of the biggest surprises, though, was “True Gravity,” a double guitar-driven instrumental that Haynes wrote with founding Allman Brothers guitarist Dickey Betts. The song hasn’t been played since 2000, the year when Betts left the band on strained terms. Its sudden inclusion on the set list seemed like a nod of respect to the influential guitarist, at the very least–it has long been the wish of many Allman Brothers fans to have Betts return on good terms. The evening’s encore, “No One to Run With,” featured clips of Duane Allman, Oakley, and Woody superimposed on a live video feed of the stage: a sweet, if slightly eerie, connection to the spirits of the band’s history.

Epic jams and powerful covers characterized the second set. A new song by Haynes, “Dusk Till Dawn,” evolved into a long digression in which another surprise occurred midway through: 28-year-old New Orleans star Trombone Shorty ran out on stage and delivered a hugely energetic, lengthy trombone solo that elicited some of the loudest cheers of the night. The Juke Horns–longtime friends of the Allmans–invigorated several songs, particularly “Don’t Keep Me Wondering.” Their punchiness matched Allman’s noticeable vitality and strong vocals. Having been frail in recent years due to a liver transplant, his renewed health adds a positive vibe to this year’s Beacon run (and contributes to the “this can’t be the end” feeling).

Backed by the Juke Horns, covers of Otis Redding’s “I’ve Been Loving You Too Long” and Van Morrison’s “And it Stoned Me” made for some of the show’s most emotionally stirring moments. The sheer power of Haynes’ blues-tinged voice wowed audience members with every mighty verse. This pair of songs riled the theatre into excitement before the set closer, an uncommon “Les Brers in A Minor” jam. Allman, Haynes, and Trucks all soloed during the first half of the song, gradually deconstructing it until their sounds faded away. They walked offstage as Burbridge, Trucks, Jaimoe, and percussionist Marc Quinones continued playing. Burbridge played an impressive bass solo and then joined the drum section, which grew to five people with the addition of guest percussionist Bobby Allende. After several minutes of intense drumming the rest of the band returned to close out the song. If anything is emblematic of the Allman Brothers’ legacy, it’s a jam that requires serious cooperation but also allows individuals to shine. Regardless of their fate beyond 2014, the Allman Brothers have cemented that legacy.

Allman Brothers Band Beacon Theatre 3/19/14 Setlist

Set I

Statesboro Blues
You Don’t Love Me*
Woman Across the River
Stormy Monday
End of the Line*
True Gravity
That’s What Love Will Make You Do^
Soulshine^^
Ain’t Wastin’ Time No More*

Set II

Midnight Rider#
Dusk Til Dawn##
Don’t Keep Me Wondering$
I’ve Been Loving You Too Long$
And It Stoned Me$
Les Brers in A Minor* > bass and drums > Drums* > Les Brers in A Minor

Encore

No One to Run With*

Notes

* with Bobby Allende
^ with Juke Horns, Scott Sharrard, Lincoln Schleifer
^^ with Juke Horns and Lincoln Schleifer
# with Lamar Williams Jr.
## with Trombone Shorty
$ with the Juke Horns