As he stooped to the floor of a bombed-out cathedral in Germany, picking up a few bits of colored glass, Army chaplain Frederick McDonald had no grand plan in mind.

"I guess no one will call this looting," McDonald told a fellow chaplain.

The year was 1945, and in the last stages of World War II, McDonald was crossing Europe with Allied troops led by Gen. Omar Bradley, seeing villages that had nearly burned to the ground, families mourning their dead, verdant fields torn up and left cratered by bombs.

"Saddening to me were the number of church towers shot down, those upward-pointing symbols of the majesty of God," he wrote in his memoirs.

To remember those shattered sanctuaries, McDonald collected pieces of glass from two dozen churches in England, France, Belgium, Holland and Germany, tucking them in envelopes and mailing them home to his mother.

Now, more than a half-century later -- and nearly four years after McDonald's death -- this wreckage of war has been transformed into a prayer for peace, a work of beauty.

A team of artists has created 25 stained-glass windows incorporating the fragments McDonald collected. Early next year, "Remembered Light: The McDonald Memorial Peace Windows Project" will be displayed in a national park in San Francisco, the city where McDonald lived for the last two decades of his life.

"He would be thrilled," said his sister, Elizabeth Parsons, 94, of Seattle. Parsons saw the first few windows on a visit to her brother several years ago, but illness will prevent her from traveling to the completed exhibit. "He was just so delighted that something like this could finally happen."

It almost didn't. In the decades after the war, the glass bits remained in a box, still inside their envelopes, while McDonald's work as an Episcopal priest and his love of adventure took him to Asia, Africa, Europe, Hawaii and even the North Pole.

But in 1999, with McDonald in his nineties, a string of coincidences set the project in motion.

It started with a dinner conversation in which a recently widowed friend wondered aloud what to do with colored glass left behind by her husband, a stained-glass hobbyist.

McDonald mentioned his glass fragments, and friends at his retirement community were immediately intrigued. Soon they spread the collection out over a large table, placing the envelopes in a grid marked with yarn.

One friend contacted a nearby stained-glass studio, which sent French-born artist Armelle Le Roux to meet McDonald.

"He was amazing," said Le Roux, 36. "He was the kind of person who had an incredibly journalistic memory of detail but also a very caring, very human approach."

McDonald had thought about combining all the pieces in a single window, or perhaps a triptych. But his rich memory of sites and stories convinced Le Roux that each should have its own art piece.

One poignant story came from Wiesbaden, Germany, where a third of the town had been leveled in a single 20-minute bombing raid. In the ruins of a chapel there, McDonald met a cleaning woman who said that when the bombs hit, she had been rushing to a shelter, carrying a child. The blast blew the youngster from her arms, and she never saw the child again.

The finished art pieces range from 11 inches to several feet across, with McDonald's shards making up just a small portion of each. In one, the bits he collected are notes on a musical scale; in another, they are headstones on hastily dug graves.

Le Roux and McDonald conferred regularly for more than two years as the windows took shape. When he died in 2002 at 93, a dozen had been finished and six more had been designed.

Many of McDonald's war experiences are detailed in a 465-page memoir he published in 1995 as "Remembered Light," a title borrowed for the windows project.

In it, he said his first reaction to seeing damaged churches was anger toward "those barbaric Germans." Then he realized that some church towers had been blasted by advancing Allied forces to keep the Germans from using them as observation points.

"Remembering this did not make me feel much better," he wrote.

When the war ended, McDonald was selected to deliver a 15-minute sermon broadcast back to the United States by NBC radio. "Days of war are hard times and breed many griefs," he said. "They are, too, times of testing and development of character. The reward that remains, however, is the peace."

His book mentions his glass collection and offers glimpses of his sense of humor: "My persistent interest caused some of my friends to accuse me of carrying rocks in my Jeep in case I found some church windows unbroken."

In February or March, the finished windows will be displayed at the Presidio of San Francisco, a military camp dating to the 1700s, which became part of the Golden Gate National Recreation Area in 1994.

Initially, they will be shown in a former officers club, but their permanent home will be the site's Spanish-mission-style chapel, undergoing a three-year, $3.5 million renovation by the nonprofit Interfaith Center at the Presidio.

"We're hoping to make it so you can take a walk through the chapel, downstairs and up, and see the sequence of places Fred went," said Paul Chaffee, executive director of the center.

A short video welcoming visitors will include footage of McDonald shot early in the project. "He was a man of peace and appreciated peace," Chaffee said. "His hope was that light would shine through these again in spite of the bullets."

McDonald's own words have been etched or painted onto the windows, giving the viewer a sense of his thoughts and perspective.

On one, showing a shadowy figure emerging through a door frame, McDonald asks, "Who is he? . . . Does he have a message for us? Can he in any way clarify the bafflement we feel for that great irrationality we call 'War'?"

Artist Armelle Le Roux shows a work depicting war graves in Maastricht, Holland. The glass shards were collected in 1945 by the late Frederick McDonald.

In 2002, McDonald displayed a 1945 photo of himself in bombed- out Trier Cathedral.