When Jean Butler assembled a dozen local musicians for a PTA show in 1986, she never could have imagined that the Amherst Town Band would eventually triple in size and play internationally.

A celebration of the band’s musical memories will take the form of a 20th anniversary concert Tuesday on the Amherst Town Green at 6:30 p.m. "Then and Now," the program’s theme, will include many past favorites, as well as a visit from Butler, the band’s original matriarch and conductor, who, along with husband Irv, relocated to Florida a few years ago.

"We’re very excited and gratified the band has flourished," she said. "We felt honored to be invited back. We were real touched. It’ll be nice to see our friends."

Despite its humble beginnings, the Amherst Town Band has grown to become a regional favorite for concerts all year. Organizing the first musicians in 1986 required assistance from the town.

"I went to Pete Houston, who was in charge of recreation in Amherst and asked if he’d help me get a place to rehearse. He also served as our announcer," Butler said.

Trombone player Tad Thompson of Wilton, who joined the group about 15 years ago, gives a lot of credit to Butler’s efforts in those early years."Jean was the band. She embodied the fun, spirit, energy and commitment. There was no nucleus in the Amherst/Milford area. Jean pulled a pit band together for a PTA show 20 years ago and said, ‘There’s a lot of talent here. There’s no reason we can’t have a band.’ Over a period of time, she was able to attract a number of musicians. She and Irv ran the entire band including rehearsals, arrangements and publicity," Thompson said.

When the Butlers left the band in 2002, French horn player Pat Anderson stepped up to the conductor’s podium and took the baton from Butler. In addition to her duties with the Amherst Town Band, Anderson serves as choral director at Souhegan High School. Thompson said Anderson was a good choice to replace Butler.

"A lot has to do with the conductor," he said. "If you don’t click on a musical level, you don’t go. Jean was able to do that over the years. Pat has the same welcoming supportive attitude and energy," he added.

Hampton Falls resident Richard Ridolfo, who plays trumpet, seconded Thompson’s endorsement of Butler’s successor.

"Pat does an excellent job getting us ready and plans the music well in advance. After Labor Day, we’ll start prepping for Christmas. The band is very well prepared and does a great job at sight-reading, which wasn’t so when we started. It’s turned out to be a very good band. We get nice praise from people in the community," Ridolfo said.

Ridolfo is one of only two original remaining members of the Amherst Town Band. At 62, the owner of an antiques and train shop in Hampton Falls continues to commute to Amherst for rehearsals and show performances.

"People thought when I moved to Hampton Falls, I wouldn’t stay involved," he said. "It’s not a big imposition on your time, about an hour and a half each week. We play just enough venues not to impose on your schedule."The band’s venues have gone well beyond the local Fourth of July and Christmas shows, according to Thompson, whose personal favorite is the annual performance at York Beach, Maine.

"They have a big gazebo on the shore and lawn. They get huge crowds of 400 to 500 people that listen to the band. When there’s a sunset, it doesn’t get any better than that," Thompson said. The group has also played twice in Wales with musicians who have performed in New Hampshire twice in the past dozen years.

The Milford Haven band performed as part of Milford’s bicentennial celebration in 1994. Four years later, the Amherst Town Band was invited to play at several concerts and parades in Wales. The Welsh musicians returned in 2000 and are expected to visit New Hampshire for a third time next year. Thompson was impressed with the hospitality and enthusiasm received from their friends in the United Kingdom."They were very gracious hosts, and their country has a rich history. When we parade over there, crowds are huge in the burgs and hamlets, 10 to 20 deep watching us go through," he said. Despite frequent cloudy and rainy weather in Wales, the show always goes on, according to Thompson. "If they waited for good weather, they’d never do anything."

Retired conductor Butler didn’t remain retired for long after moving to The Villages in Florida, a community of 60,000 seniors just north of Orlando.

"It’s not typical," Butler said. "It’s a community with life. We have a Dixieland band, swing band, strolling band and two concert bands. I conduct the concert band and co-conduct the New Horizons Concert Band, which encourages seniors to get back into music. We have people who haven’t played in 60 years and have the confidence to do it again," she adds.

Thompson recalls an incident where a planned practical joke was played on Butler one night.

"One time, I think it was Jean’s birthday, on one piece, we (secretly) decided to play out of tune. She gave us that look, ‘What in the world are you doing?’ Then she collapsed in gales of laughter," Thompson said.

Butler believes hard work and dedication can be fun.