NBC and CBS were both founded as radio networks in the 1920s. Later on, NBC would have two radio networks for the United States. These networks were the Red Network and the Blue Network. They soon began television stations in the 1930s. In 1943, the U.S. government noticed how unfair it was for NBC to have two networks. They forced NBC to sell one of their networks. NBC chose to sell the Blue Network. Later on, the Blue Network became the ABC.