Photography starts off in 1839 by the research of Sir John Herschel, who also the one that used the term "Photography". The word is from greek words for Light and writing. So in other word Photography means "writing with light".
The concept of photography, exposing light to a silver based medium to create a negative, has made people thinking of building a portable darkroom to store the negatives so that they won't be ruined by the sunlight. They were thinking to build a camera. When we talking about camera in the early 20 century, we"re talking about a huge wooden box that was mounted on a huge wooden tripod, so heavy that a photographer at that time must have an assistant to help carry the camera. The negatives were also huge. Made out of glass plate filled with silver and other light-sensitive materials, the smallest size of these glasses are 8x10 inch which until now are still in use ( for large format photography, no longer plate though, but film.), but most of the time the photographer use a negative that as big as the final print would be.
This idea of large format is not very portable, the camera is heavy, the setup takes long time, many people but professional wouldn't dare to "kill" himself lugging big camera, plates, and tripod just to take family snapshot on holiday. So, there were some people who experiment with the ideas to shrink the negatives and make smaller cameras, so that everybody can enjoy the beauty of photography at any time and any place.
One of the people that really put his thought and mind to develop this small portable camera and negatives was Oscar Barnack. He worked at the Leica company in German. Leica is one of the biggest Lens industry in the world, was formed in 1849, had contributed many advancement in lenses industry, microscopes, telescopes, binoculars, and of course, cameras.
On Early 1905, Oscar Barnack started experimenting with different kind of film.