Social movement
It was initially founded as Union of the National Youth Legions, which gained popularity among youth by using propaganda methods, popular in Nazi Germany at that time, including a march from Sofia to Veliko Tarnovo. It rivaled for political support with other popular nationalist organizations such as the Ratniks and the National Social movement. By 1939 the already renamed UBNL had 75,000 members, and while in that year it was formally banned by the pro-Nazi government of Tsar Boris III, it continued to function and was supporting the close alliance of Bulgaria to Nazi Germany.