Well, how are we able to determine who was the most influential, or for that matter how do we know of these people to begin with? What gives us that ability? Knowing they existed, or their works, and how is this done...
Writing mainly, sure certain oral histories can be passed down but then it's a case of operator where each new person hears a slightly different story, and at the end those people are just fictional characters.
Now writting is just symbols, unless you know how to read. Before the printing press most people were illiterate as books had to be copied via hand. The printing press made knowledge of these people available to everyday men, enabling them to learn to read and write, which in turn made common people aware of these various figures.
That's why I say Gutenberg
