What is the origin of manga? The word is composed of two Japanese caracters—the first meaning "informal" and the second meaning "picture"— and has been used to describe various comical images for at least two centuries.
The word itself was popularized by the famous woodblock print artist Hokusai, but it was not invented by him. The first clear examples of such sequential art are the picture scrolls of medieval Japan, which combine pictures and text to tell stories. These scrolls look and work like modern manga or comics in many ways, but there is a crucial difference: whereas modern-day manga are produced for mass consumption, picture scrolls were singular works of art produced for an elite audience.
The actual manga starts after World War II, because the american influence (Marvel, Disney, etc) was mixed with the japanese tradicional art.
