Short answers, pulled from the story.
The 1492 ascent of Mont Aiguille by Antoine de Ville is widely recognised as the birth of mountaineering because it was the first climb of genuine technical difficulty to be officially verified. The sport took its modern organised form from the founding of the Alpine Club in 1857 and Alfred Wills's ascent of the Wetterhorn in 1854, which inaugurated the Golden Age of Alpinism.
Sir Edmund Hillary and Tenzing Norgay reached the summit of Mount Everest on the 29th of May 1953, approaching from the south side in Nepal. It was the culmination of several British-led attempts, including a 1922 expedition that reached 8,320 metres before an avalanche killed seven porters.
Reinhold Messner, from the Dolomites in Italy, was the first to climb all fourteen eight-thousanders, completing the last of them by 1986. He was also the first person to summit Everest without supplemental oxygen, achieving that in 1978 alongside Peter Habeler.
Expedition style involves multiple trips between camps to stock supplies, fixed ropes, larger teams, and a higher safety margin, and is standard in remote high-altitude ranges like the Himalayas. Alpine style means a single continuous ascent with no backtracking, fewer supplies, and a smaller team, summarised by the mantra "light and fast."
Altitude sickness is a central hazard; without acclimatisation, it can progress to high-altitude cerebral edema or high-altitude pulmonary edema, both of which can be fatal within 24 hours. From 1947 to 2018, mountaineering accidents in the United States involved 2,799 people, and 43 percent of those accidents resulted in death.
The Piolet d'Or is the premier award in mountaineering. It is privately granted and has expanded from a single recognition to multiple awards.