It was a kind of coming-out party after 18 months of staying in. A reconnection between Philadelphia’s artists and the culture mavens who have missed them. An affirmation that Philadelphia’s arts sector is back.

This was the hopeful messaging Saturday at the Kimmel Center, where the doors were thrown open for a day of Beethoven, hip-hop, opera, poetry readings, and more. About 50 arts groups were represented, and the event, dubbed “Arts Launch 2021,” marked the first fully public event for the city’s largest arts presenter since it shut down for the pandemic in March 2020.

Of course, the public health crisis isn’t over. As arts groups wade into the 2021-22 season, they do so warily with a new set of requirements for audiences to be vaccinated and masked and, in some cases, distanced. Still, with their finances battered and a newly urgent sense of mission, arts leaders regarded Saturday as an important milestone.

“We’re open, as is the Philadelphia cultural community opening,” said Kimmel Center chief operating officer Ed Cambron.

Many groups have continued to perform during much of the past 18 months, either with greatly reduced audience capacity or through online presentations, or both.

But much hinges on the return of live concerts and the ticket revenue that comes with them.

The Kimmel, which is both landlord to its resident companies and a presenter itself, is slated to host blockbuster musical Hamilton this fall at the Academy of Music. Ticket sales have been strong — the center’s Broadway series has more than 12,000 subscribers so far — though many seats remain available.

» READ MORE: The giant list of plays and musicals on the Philadelphia theater circuit this fall

Saturday’s curtain-raiser brought no stars from Hamilton, but the performances added up to a broad representation of what’s to come. In one corner of the Kimmel plaza, the Philly Pops Big Band, conductor David Charles Abell, and singer Michael Andrew paid tribute to Frank Sinatra, while in the other patrons could spin a wheel to win prizes or tickets to shows like Stomp.

Representatives from the Kimmel’s resident companies as well as other groups like Network for New Music and First Person Arts were on hand to chat about the coming season.

“The kids are excited,” said Joan Myers Brown, referring to members of the group she founded, Philadanco, which performed Saturday in the Perelman Theater. The troop hasn’t seen live audiences since the start of the pandemic, she said, “and there’s nothing like live for the performers. The response from the audience makes a difference.”

You also can’t beat the bond established when you get to take a selfie with the Mouse King. The Nutcracker villain, posted outside of Verizon Hall, was doing a brisk business of fist bumps with children and letting them touch his crown.

He said he had missed dancing during the pandemic and was looking forward to the company’s annual production this December.

“I can’t believe I have this opportunity,” said the Mouse King, known outside of his costume as dancer Felipe Valentini, new to Philadelphia Ballet II.

It was a chance to hear the Philadelphia Orchestra that brought Dianne Chenault from Tacony to the Kimmel for the first time — that, plus the fact that she had had trouble ordering tickets to Stomp over the phone.

“I’m really happy they’re doing this,” she said of Saturday’s arts sampling. About 5,800 visitors to the five-hour event were counted, a Kimmel spokesperson said.

The Philadelphia Orchestra not only performed, but did so in a packed 2,500-seat Verizon Hall where they were greeted with a standing ovation before even playing a note. This year the ensemble is cycling through a lot of Beethoven, and music director Yannick Nézet-Séguin was present to lead the ensemble in the composer’s Symphony No. 3 and Jessica Hunt’s Climb.

Earlier, a historical marker was unveiled in front of the Academy of Music dedicated to one of Nézet-Séguin’s predecessors: Leopold Stokowski, the orchestra’s third music director a century ago still regarded as a pioneer in technological innovation and adventurous repertoire.

» READ MORE: Classical music to see in Philly this fall

Patrons returning to the Kimmel will find that much has changed since March 2020. Pennsylvania Ballet changed its name to Philadelphia Ballet. The boards of the Kimmel Center and Philadelphia Orchestra voted to consolidate under a single parent company, with orchestra chief Matías Tarnopolsky assuming leadership of the new entity. Longtime Kimmel president and CEO Anne Ewers will retire. The quasi-merger is expected to become official this fall, likely in November.

The arts center’s box office has moved to the basement of the complex, and in its former Spruce Street spot a cafe is slated to open in early 2022. The plaza has been reopened for public activity after the long closure.

But the change all arts leaders are nervously trying to suss out lies with audiences, and it’s a shift they hope they don’t find. Have bonds with orchestra fans and balletomanes weakened? Has the pandemic given audiences a chance to get out of the habit of going out to the theater?

“I think we have to be realistic,” said the Kimmel’s Cambron. “Some people probably have changed their habits, and others may be voracious” in the way they consume cultural events.

“Hopefully,” he said, “it evens out. But who knows?”