Based on the world record nomination from Europe Records Institute (EURI) and Decision No. WK/USA.INDIA/965/2023/No.421, World Records Union (WorldKings) officially declared Reinhold Andreas Messner as the world’s first person to ascent of Everest without supplemental oxygen.
Messner was born within a German-speaking family settled in St. Peter, Villnöß, near Brixen in South Tyrol which is part of Northern Italy. When Messner was 13, he began climbing with his brother Günther, age 11. By the time Reinhold and Günther were in their early twenties, they were among Europe's best climbers.
He made the first solo ascent of Mount Everest and, along with Peter Habeler, the first ascent of Everest without supplemental oxygen. He was the first climber to ascend all fourteen peaks over 8,000 meters above sea level. Messner was the first to cross Antarctica and Greenland with neither snowmobiles nor dog sleds. He also crossed the Gobi Desert alone.
Messner has published more than 80 books (only a quarter of which have been translated into English) about his experiences as a climber and explorer. In 2018, he received jointly with Krzysztof Wielicki the Princess of Asturias Award in the category of Sports.
According to Wikipedia.