Famed Swiss mountain guide Erhard Loretan, one of the few climbers to ever reach the summits of all 14 of the world's peaks above 8,000 meters, has died in a climbing fall on his 52nd birthday. Swiss police said Friday that Loretan died leading a client up the summit ridge of the Gruenhorn, in the Bernese Alps. The accident occurred on Thursday noon. The pair had skied up part way, then roped up for the final ascent.

They fell for unknown reasons at 3,800 meters (12,500 feet) up the 4,043-meter (13,264-foot) peak. Loretan died at the scene, police from the Swiss canton (state) of Valais said. His 38-year-old Swiss client was flown to a hospital in serious condition.

Police are still investigating.

Loretan, originally from the canton of Fribourg, began climbing at age 11. He climbed his first 8,000-meter peak, Pakistan's difficult Nanga Parbat, in 1982. It took him 13 years to make it up the other 13 eight-thousanders.

His 1986 ascent of Mount Everest, without bottled oxygen and in a night-time push with climbing partner Jean Troillet that took just 40 hours, stunned the alpine climbing world and made headlines in climbing magazines and newspapers.

"We didn't intend to climb Everest in two days, we just set off and we were fortunate to do it in two days," he told last year's Trento Film Festival in Italy, in a video posted on its Web site. "I think that we were young, in love with climbing. When you're in love you'll do anything, it wasn't sacrifice, it was all normal. We didn't think we were doing incredible things, it just all seemed normal."

It also cemented his reputation as one of the world's top mountaineers after becoming the third person, behind Italian legend Reinhold Messner and Polish mountaineer Jerry Kukuczka, to climb all the 8,000-meter peaks. Last year, Spanish climber Edurne Pasaban became the 25th, and only the second woman, to pull off that feat.

"Fi rst of all I'd like to thank the mountains, for almost 40 years they have allowed me to climb, and with this passion I've lived an extraordinary life up to now, that's why I'd like to thank them," he told the film festival, calling himself fundamentally a solitary figure.

"I now want to share this passion more with others, and it's because of this that being a mountain guide is a good profession because you can help someone who dreams about climbing mountains. This is something very beautiful."

Loretan's legendary exploits in the mountains were nearly overshadowed by the debate he prompted on babyshaking in Switzerland after he pleaded guilty to negligent manslaughter in the death of his 7-month-old son.

In 2003, he was given a four-month suspended sentence for shaking his baby son - for a couple of seconds to stop him crying, he said. He told police he put the child to bed and the crying stopped. He later called an ambulance.

The case's notoriety also led to new research showing many parents were unaware that infants can die from being shaken for only a few seconds, because of weak neck muscles.