Where exactly the origins of ‘gravel biking’ lie is a matter of much debate, especially here in Europe. Many claim that the origins clearly lie in cross-country or cross-sport, as modified racing bikes were already being ridden across the fields, especially in Germany and Belgium in the 1920s.
In America, on the other hand, road cycling over hill and dale became established as a result of mountain biking and cycle touring in the 70s and 80s. In his documentary film ‘Gravel - A Love Letter’, filmmaker Justin Balog examines precisely this and allows a few exciting protagonists to have their say. Although the film is completely branded Pearl iZumi, this does not detract from the interesting and worthwhile aspect of this documentary.
You can see more films by Justin Balog here: Justin's official website