GUILDERLAND — Jane DeRook saw the beauty in ballet and wanted to share it, not just with her own daughters but with the children of Guilderland, many of whom she tended to as a doctor.

She founded the Guilderland Ballet in the late 1960s, at first with classes in the schools after hours and later in a dilapidated barn that volunteers — many of them the parents of dancers — fixed up.

During its heydey in the 1980s through the 1990s, hundreds of people over the course of a weekend would flock to Tawasentha Park to see the Guilderland Ballet perform.

Dr. DeRook ran the Guilderland Ballet for 45 years but now the barn, owned by the town, is being repurposed. She and her daughter Nancy, who had danced and taught there, took a bittersweet look back at the Guilderland Ballet.

Before starting the school that eventually would help thousands of local children learn to dance, Dr. DeRook was already well known in Guilderland because she and her husband, the late Franz DeRook, ran a popular general-practice medical office out of their home on Fletcher Road in Westmere.

Asked how she and her husband divided the patient load, Dr. DeRook, who is now 90, “Some people preferred a woman. And for some reason I got the babies. I had a special table for them. They were so small.”

Growing up in the Netherlands during World War II — “Germany overruled us, and the English were bombing us sometimes by mistake,” she said — Jane DeRook never saw a ballet performed in her early years. Her first was in 1964 at the Saratoga Performing Arts Center, after she had finished medical school in the Netherlands, moved to the United States with her husband, who was also Dutch, and had several children.

“I never saw anything as beautiful in my life. I love music, but this is music in form, so double pleasure,” she said.

After she went with a friend to observe a ballet class taught at a local firehouse, she realized that Guilderland children did not have any good ballet education options locally. It was then, in 1968, that she started the ballet school, hiring instructors to teach after-school classes in the Guilderland schools.

Classes continued and thrived for almost 20 years before Dr. DeRook found a permanent home for the school, her daughter recalled. In 1987, Dr. DeRook was talking to local developer Armand Quadrini, and mentioned that she had a dance teacher who liked to compose, and he said that he had an old barn with a piano in it, on the site of the old Mill Hollow mission on State Farm Road — previously a monastery — where she could play.

The teacher was at the barn practicing one day and remarked to Dr. DeRook that it would make a good dance studio, her daughter said.

Armand Quadrini began renting the dilapidated barn to Dr. DeRook for a dollar a year, and promised to let the school stay as long as it remained the Guilderland Ballet.

The doctor and many parent volunteers began the work of renovating the barn into a modern dance studio, a work that was a labor of love.

In 1995, Quadrini told Dr. DeRook that she could have the property’s old church, and a dance teacher had the idea to have the church building moved over 15 feet, so that it could be connected to the old barn through the construction of an office in between.

This work, which was completed in 1998, cost between $10,000 and $12,000, Nancy DeRook estimates, and was all done by volunteers. Now the school had two dance studios, with barres, windows, and state-of-the-art marley floors with wood underneath. “Wood rebounds,” said Nancy DeRook, “which is better for the knees. A lot of studios were built on concrete.”

The Ballet Barn as it is now, with its two modern studios, “wouldn’t exist” without those volunteers, said Nancy DeRook recently. ‘The volunteers created it with their own money from bake sales, and with their own hands.”

Through the 1980s and 1990s, Nancy DeRook says, the school brought hundreds of people out one weekend each spring to see ballet performances at the theater in Tawasentha Park.

In early 2003, the plans that Quadrini had had for the former monastery’s lands — to make them into a retirement community for residents aged 62 and older — fell apart when he became unable to get financing, and the town rejected his request to lift the age restriction.

Quadrini’s lands — including the Ballet Barn — were set to be foreclosed on and auctioned off. A petition asking the town to bid on it got a couple of hundred signatures, but then-Supervisor Kenneth Runion said that there was not enough time to follow procedure, which would involve taking the matter to a number of board meetings.

The lands were indeed sold, but the ballet got a reprieve later that year, when the company that bought the land and buildings decided, amid public uproar over the fate of the Ballet Barn, to donate the barn to the town.

Dr. DeRook told The Enterprise in 2003, “I’m positive that, if we hadn’t taken the building under our wing, it would have been long gone.”

She also told The Enterprise that year that Runion didn’t tell her about the reprieve; she learned about it when she was watching a board meeting on live television and saw him announce it.

The town had for many years helped support the ballet program by paying for heating bills at the barn and doing its payroll, but that support had ended in about spring of 2002, Nancy DeRook said.

The school continued for another decade after its 2003 reprieve, but over that time began to see its membership drop off. Dr. DeRook told The Enterprise in 2008 — its 40th anniversary year — that she saw girls starting to move away from ballet, toward soccer.

The school expanded its offerings to include yoga and Pilates as well as ballet and jazz, and Dr. DeRook continued to lead the school even after her retirement from her medical practice.

Nancy DeRook says she taught the last class at the barn in August 2013. She and her mother continued to try to find ways to re-establish it “as a different type of studio, more open to other venues like yoga,” said Nancy DeRook. She went often to the barn, she says, to check on and maintain it.

She also went to see Supervisor Runion and his staff several times to ask for their help in advertising the school’s planned new programs, but, she says, they were not interested.

Near the end, she says, there were two electrical bills that they were unable to pay, and for which she asked for some help from the town. Runion told her, she says, “Absolutely not.”

Reached at his home in Florida, Kenneth Runion responded, “As I recall, the Guilderland Ballet just kind of ceased their program, and had kind of abandoned the building, so, in order to make sure the building wasn’t broken into, or there wasn’t any kind of damage, I think the locks were changed.”

He added that the town was getting notices of “a lot of unpaid electric bills” toward the end.

Current Supervisor Peter Barber said recently, “It is town property, and, if the town’s not renting it out, and the building’s not being used, it seems prudent to change the locks.”

The Guilderland Ballet still had all of its possessions inside the barn, says Nancy DeRook, including many hand-sewn costumes and all of its photo albums.

Nancy DeRook stopped at the barn one day in spring of 2014, tried to put her key in the lock, and found that the locks had been changed.

She went home and told her mother about the changed locks.

“It was like somebody smacked me in the face,” said Dr. DeRook about the changed locks. “I’m not quick to cry, but I could have cried.”