Stephen Sondheim’s long life was punctuated by key Philadelphia-area moments, both at the very beginning and in his final decade. The composer/lyricist and titan of musical theater died Friday at age 91.

His first musical was written in 1946 when he was a teenager at George School in Bucks County, from which he received its alumni award in 1996. A world away from that, starting in 2013 when Sondheim was recognized as the greatest theater composer of his time, Arden Theatre producing artistic director Terrence Nolen helped facilitate one of Sondheim’s many career accolades.

In Bucks County, a Ouija board would be needed for reminiscences of By George, the long-buried satirical musical he wrote before his graduation from the Newtown prep school. But after a merciless critique of the show by Oscar Hammerstein II, the lyricist of South Pacific who lived in the area and mentored him in his George School years, Sondheim learned so well from his mistakes that by 1957 he was writing lyrics for West Side Story. Hammerstein was sometimes described as a surrogate father who clearly believed in tough love. It didn’t go unnoticed. “Our mission is to educate students so that their lives speak authentically and benefit others. Stephen’s life did just that — in his case it, of course, also sang,” said J. Samuel Houser, head of George School.

Decades later, the composer of Sweeney Todd, Sunday in the Park with George, A Little Night Music, and songs such as “Send in the Clowns” had achieved hard-won comfort with being a public figure — one who had the power to raise the visibility of theaters that he thought were doing right by his work.

Nolen was one of those people. He made Sondheim shows a specialty at the Arden — 16 to date — and Sondheim saw many of them on video. In 2013, Sondheim was making public appearances with theater experts, discussing his work and the methods behind it, and taking questions from the audience. Nolen was drafted as one of the interviewers for one such event at the Wilmington Grand Opera House. In 2015, Sondheim was the recipient of Arden’s first Master Storyteller Award even though a power outage forced the ceremony to move to the nearby Hamilton Family Arts Center so that the show could go on. Yes, there’s a story there.

And I had my own stories to contribute to Sondheim’s many accolades. During my life as a journalist, I interviewed him on multiple occasions. Nolen and I decided to compare notes on the never-ending question of who, exactly, was this nervous, ultra-meticulous man who changed Broadway.

Nolen and I sat down to reflect on our work with Sondheim. The conversation has been edited for clarity.

David Patrick Stearns: Tell me about how Sondheim fared during the famous 2015 [Arden] awards-ceremony snafu.

Terrence Nolen: He called me the night before the event and said, “I’m not feeling well. I’m going to be there, but I just want you to know that I’m not feeling well...” But he enjoyed the adventure of it. He totally did. He had a grand old time with it. His lawyer had told me that doesn’t like to be fawned over ... so at the ceremony, [fellow composer] Jason Robert Brown said “Now I can say all of the things I’ve wanted to say to him because he can’t leave.” Then Sondheim shouted out from the audience, “Taxi!”

DPS: And it was there that he figured out that he was the only one in the world who addressed you as “Terrence” rather than “Terry.”

TN: I wrote him many times with questions about his work, and always began “Dear Mr. Sondheim.” He wrote back “People call me Steve. And if I may call you Terrence ...” Which I loved.

DPS: He had those Old World manners. When I asked him for an interview, he would graciously turn me down in a message on my home answering machine — though adding that he hoped never to give another interview again. When I did interview him, he drank nonstop. But this was in the late-’80s.

TN: He was a shy person in many ways. After we did the event in Wilmington in 2013, we got in the elevator and he leaned against the wall and exhaled. ... He said, “I had to work really hard to get good at that [talking to people one on one]. It took a long time.”

DPS: I thought of him as the genius next door, I often saw him out at cutting-edge theater in New York.

TN: He was so curious about theater and why people made the choices that were made. He loved new writing. He just came to life in the way he talked about theater. ... I wanted to do a production of Sunday in the Park that took place largely in Georges Seurat’s mind, with minimal scenery and also using video so that we saw the action from Georges’ perspective. I also wanted to use Michael Starobin’s original orchestrations — no reduction — so that the music filled the space — and we could “hear” the musical through Georges’ ears. He was very enthusiastic and wrote a letter of support that we used to get additional funding to make this happen.

DPS: He was kind of a helicopter parent with his own shows. Several of them are flawed, like Follies and Merrily We Roll Along. Fine! Some shows are like that. But he couldn’t stop revising them. And they didn’t get better. Pacific Overtures is not one of the problem shows, but when I told him I was fond of it beyond all the others, he said, “If you like that you’ll like anything!”

TN: He was relentless in his pursuit of what he believed to be true. He was laborious about the details. When I was with him, I realized that he lived that. He required enormous specificity in his work but also enormous passion and compassion. I felt that he balanced all of that in a really inspiring way.

DPS: In so many Broadway songs, everything is either agony or ecstasy. But in one song from Sondheim’s Company, a married man sings about how he’s both sorry and grateful for his relationship. That’s real.

TN: It’s about the inherent contradictions and complexities of living in this world. ... There’s something so deeply personal about his work that folks connect to so personally that in the first preview of one of his shows, you can feel the audience just give themselves over. The use of language is so astonishing and the music can crack you open.