Sister Wendy Beckett at the Isabella Stewart Gardner Museum in Boston in 1997. (Victoria Arocho/AP)

Sister Wendy Beckett, a Catholic nun who left her cloistered life in the British countryside to become an unlikely international celebrity by presenting television programs on art history, died Dec. 26 at a residential care facility near Quidenham, England, where she lived on the grounds of a Carmelite monastery. She was 88.

A spokeswoman for the monastery, Gina Rozner, confirmed the death. The cause was not disclosed. Sister Wendy had a history of heart ailments and strokes.

Sister Wendy retreated to a life of seclusion in 1970, officially designated a consecrated virgin by the Catholic Church. She lived alone in a trailer, spending seven hours a day in prayer and translating Latin religious tracts.

After receiving permission from the church, Sister Wendy began to study art history, primarily through books and reproductions on post cards. She began to write for magazines and in 1988 published the first of more than 30 books, “Contemporary Women Artists.”

In 1991, she appeared in a BBC documentary about the National Gallery in London, discussing the paintings of Rembrandt. Although she was on-screen for only four minutes, viewers were transfixed by the bucktoothed nun in full religious habit and oversized glasses, speaking with wit, warmth — and a slight speech impediment — about one of the greatest artists in history. She soon became the host of her own BBC show, “Sister Wendy’s Odyssey,” a series of 10-minute segments in which she described various works of art.

At the beginning, Sister Wendy was shown emerging from her book-filled trailer, as if making her first forays into the wider world of art — which, in large measure, was true.

She proved to be charming and at ease in front of the camera. Always speaking without a script, she became known to her producers as “one-take Wendy.” With her expressive face and hands, she described art with a mixture of glee, ecstasy and wonder.

“I force myself to look at it, take it in and tell you in words what I have seen, which is not an easy thing to do because it means going deep into your reactions,” she told the New York Times in 1997. “I can’t do anything without the work of art being there to draw it out of me.”

For her second series, “Sister Wendy’s Grand Tour” (1994), she made her first trip to continental Europe, visiting museums in Paris, Rome, Amsterdam, Madrid, Florence and Berlin. (By then, she had an agent who substantially raised her fee and negotiated a clause that allowed her to attend Mass every day.)

Sister Wendy became a media sensation, and her two series were the most successful arts programs on British television since Kenneth Clark’s “Civilisation” in the late 1960s. They often attracted a quarter of the British TV audience.

Many viewers found her programs inspiring, but some were shocked by Sister Wendy’s enthusiastic appreciation of the carnal nature of many artworks, including her oft-repeated description of a nude couple: “I love all those glistening strands of his hair, and her pubic hair is so soft and fluffy.”

She answered the objections with a stern rebuke based on her reading of scripture.

“I’m absolutely astonished and bewildered to find people commenting on my delight in a naked body,” she told The Washington Post in 1997. “Never, ever, has anyone suggested that parts of the body were not quite right, that God made a mistake, that they should be passed over. It’s appropriate to comment on everything in the painting. I’m not going to deny God’s glory by pandering to narrow-mindedness.”

In 1994, Sister Wendy published “The Story of Painting,” a coffee-table book examining more than 200 paintings throughout history.

It formed the basis of her most ambitious TV series, “Sister Wendy’s Story of Painting,” which appeared on the BBC in 1996 and on PBS stations in the United States a year later.

For the 10-part series, she visited 12 countries and traveled more than 30,000 miles to chronicle painting from prehistoric times to Picasso.

She brought a distinctly 20th century interpretation to the work of 14th century painter Giotto — “my dear, dear Giotto” — whose paintings led the way to the Renaissance.

“Think of how dark it was outside without him, as if everyone was listening to the radio,” she said. “And suddenly he comes forward and it is, yes, like the coming of television. Suddenly people have this great color. This television.”

Explaining how the work of the tortured Vincent van Gogh resonates so strongly with people more than a century after his death, Sister Wendy said, “We are an anxious, neurotic generation, and we warm to this neurotic man, struggling so bravely to impose calm upon the turmoil of his mental stresses.”

She had an appreciation of abstract art, but she clearly preferred traditional figurative works. Her favorite artists included 17th century Spaniard Diego Velázquez — “the greatest painter the world has ever seen” — 19th century French painter Paul Cézanne and her British contemporary, Lucian Freud, who often portrayed people in fleshy, unflattering poses.

Sister Wendy was seldom overtly critical of any artists, although she cared little for the work of Spanish surrealist Salvador Dalí or the “really pathetic” modern British artist Damien Hirst, who sometimes put dead animals on display in containers of formaldehyde.

She developed a devoted following among ordinary readers and viewers, who stopped her on the street whenever she was out in public. But professional critics often dismissed her as an untutored interloper who didn’t understand modern trends in art or critical theory.

Time magazine’s Robert Hughes — the host of several competing television programs on art history — mocked her as a “relentlessly chatty pseudo-hermit with her signature teeth” whose observations were “pitched at a 15-year-old level.”

Sister Wendy said she deliberately ignored the jargon of the art world in an effort to make her presentations more accessible.

“I’m not a critic. I’m an appreciator,” she said in 1999. “I think great art opens us not just to the truth as an artist sees it, but to our own truth . . . You’re being invited to enter into the reality of what it means to be human.”

Wendy Mary Beckett was born Feb. 25, 1930, in Johannesburg. She soon moved with her family to Edinburgh, Scotland, where her father studied medicine. The family later returned to South Africa.

Sister Wendy read constantly as a child and entered religious life in 1946. She joined the Sisters of Notre Dame de Namur, a teaching order, and studied English literature at the University of Oxford, graduating in 1953 with highest honors. One of her professors was “Lord of the Rings” author J.R.R. Tolkien.

At Oxford, Sister Wendy maintained a vow of silence, living in a religious community and rarely speaking with her classmates. She taught in schools in South Africa from 1954 to 1970, when she began to suffer from epilepsy.

She was released from her order and lived by herself at a Carmelite monastery in northern England for the rest of her life, although she was not a member of that order.

Her final TV series, a tour of U.S. museums, appeared in 2001.

She continued to write books, including works on art history, Catholic saints and personal meditations, until 2011.

She donated all her earnings to the monastery where she lived — a monastery without a television.

Survivors include a brother.

Sister Wendy’s celebrity opened doors to world leaders, artists and journalists, and she freely indulged a taste for fine food and wine. Yet she always returned to her spartan trailer in the woods, where she prayed for hours and explored the world of art she found in books and postcards.

“I think beauty is a reflection of the light of God,” she said in a 1994 interview with NPR. “I can’t give you a better definition than that.”