The abuse of amateur rules by the Eastern Bloc nations prompted the IOC to shift away from pure amateurism, as envisioned by Coubertin, to the acceptance of professional athletes participating at the Games. The growing importance of mass media has created the issue of corporate sponsorship and general commercialisation of the Games. World wars led to the cancellation of the 1916, 1940, and 1944 Olympics; large-scale boycotts during the Cold War limited participation in the 1980 and 1984 Olympics;[4] and the 2020 Olympics were postponed until 2021 as a result of the COVID-19 pandemic.