Short answers, pulled from the story.
The most widely accepted start date for the ancient Olympic Games is 776 BC, based on inscriptions at Olympia listing footrace winners. The Games most commonly date their end to 393 AD, when Emperor Theodosius I decreed the elimination of all pagan cults; another cited end date is 426 AD, when Theodosius II ordered the destruction of Greek temples.
Baron Pierre de Coubertin founded the International Olympic Committee in 1894 at a congress held at the University of Paris from the 16th to the 23rd of June. The first modern Games under the IOC took place in Athens in 1896, with 241 athletes from 14 nations competing in 43 events.
The Oxford Olympics Study 2016 found that since 1960, sports-related costs for the Summer Games have averaged US$5.2 billion and US$3.1 billion for the Winter Games, not counting infrastructure like roads and airports. Average cost overrun since 1960 has been 156 percent in real terms, meaning actual costs are typically around 2.56 times the original budget estimate.
The United States and 65 other countries boycotted the 1980 Moscow Olympics because of the Soviet invasion of Afghanistan, reducing participating nations to 80. The Soviet Union and 15 other nations boycotted the 1984 Los Angeles Olympics in retaliation, though 140 National Olympic Committees still competed, a record at the time.
The first Winter Olympic Games were held in Chamonix, France, in 1924, and for decades the Winter and Summer Games took place in the same year. Beginning with the 1994 Games, the Winter Olympics shifted to a two-year offset from the Summer Games, after the last same-year pairing at the 1992 Albertville Games.
Sir Ludwig Guttmann organised the first multi-sport event for disabled athletes in 1948 alongside the London Olympics, originally called the Stoke Mandeville Games. In 1960 he brought 400 athletes to Rome for the first official Paralympics. A 2001 agreement between the IOC and the International Paralympic Committee formally guaranteed that host cities would manage both Games, taking effect at the 2008 Beijing Summer Games.