the lucerne sport international (later known as socialist workers' sport international) was established in lucerne, switzerland in 1920. the first unofficial workers' olympiads were held a year later in prague, czechoslovakia. the ioc had banned the losing side of the world war i from the 1920 summer olympics (germany even from the 1924 games), but the workers's olympiads were open for the "enemy" side as well. the number of participating countries was thirteen. the first official worker's olympiads were the 1925 winter games in the german town of schreiberhau, which today is a part of poland. they were followed by the first summer olympiads in frankfurt am main.