The climb was in-character for the adventure-seeker, but it also came with a greater purpose in mind.
Pippa, who became engaged to financier James Matthews earlier this month, did the climb to raise money for the Michael Matthews Foundation in honour of her fiancé's brother who died while scaling Mount Everest in 1999. He was 22 and was the youngest Briton ever to have scaled the peak at the time.
"It was humbling to have been able to climb one of the world's most beautiful mountains and raise money for a charity created in memory of an extraordinary young man who lost his life on another peak," Pippa said. "Although I have raised money in the past for the Michael Matthews Foundation, it has now become even more important to me and my family."
She added, "Although neither I nor my brother ever met Michael, we both share his spirit and passion for the mountains. We made this climb knowing he would have been there nudging us on, and we are honoured to be supporting his memory."
The Michael Matthews Foundation was established by his family and friends following his death and builds schools in remote areas around the world, including Thailand, Nepal and Tanzania.
Although her fiancé did not join the ascent, the 32-year-old bride-to-be said he fully backed the endeavour.
"It would have been good if James Matthews had been here to share the experience, something I know he would have loved to have done," she said. "Mountain climbing, though, has disturbing memories and understandably James kept his feet firmly on the ground, whilst giving us his complete support."
The Middleton siblings arrived in Zermatt a few days before the climb in order to prepare and acclimate. On Thursday they climbed a nearby mountain with their guides as a practice. Both Pippa and James found this climb very difficult and, looking back, more difficult than the Matterhorn itself.
They woke up 4 a.m. to attempt the last leg of their journey on Saturday morning and reached the summit around 7:30 a.m.
"This morning's climb has taken us a little further from our comfort zone, with lactic acid building in our thighs, a light head from the altitude and a dry mouth resulting from a combination of fear, adrenalin and dehydration," Pippa said. "For all that, though, my brother and I have loved it. Not only do we have the same ethos but we look after each other, each of us pulling our weight and working well as a team."
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