The simple answer is that skiing has been around for a very long time, with some evidence that dates skiing back at least 7,000 years in Norway. One ancient carving from 5,000 B.C. shows a skier with a single long pole.
"Snowshoe Thompson," a Norwegian immigrant to California, used the same single-pole technique as he carried the mail on skis to remote regions of the Sierra from 1856 to 1876.
The annual Birkebeinerrennet, a 54-kilometer Nordic ski race in Lillehammer, Norway, commemorates an epic escape on skis when two skillful Birkebeiner skiers brought the young king Haakon Haakonsson to safety in 1206 A.D. Other Birkebeiner races are held around the world.
Norway and surrounding countries have been always at the forefront of skiing technique, moving from straightforward Nordic or cross-country skiing to alpine or downhill. This came about with the development of the telemark turn that allowed skiers in free-heel equipment to make controlled turns at high speed. The turn is named for the Telemark region of Norway, where it was developed.
Skiing was developed for traveling, hunting, and working in snow country and, as with many products of human ingenuity, was also applied to warfare. That continued into World War II, when Finns fought the Russians on skis for four months starting in November 1939, and the U.S. Army created the 10th Mountain Division which eventually fought the Germans in the mountains of Italy, though not on skis.