 After possibly 20,000 years of occupation, the traditional lifestyles of the First Australians were disrupted by the European invaders, including disease.The area was explored by Europeans in 1835, and in 1840, Edmund Strzelecki ascended Mount Kosciuszko and re-named it after a Polish patriot and military leader Tadeusz Kościuszko.High-country stockmen followed, using the Snowy Mountains for grazing during the summer months.