In the time of the Yellow Emperor (Huángdì 黄帝, reign 01a-3) no-one knew how to write and had to remember everything, which was extremely inconvenient.
Fortunately at about this time there lived a man named Cāngjié 仓颉, who was very clever. Some say that this was just another name for the Yellow Emperor himself, since the Yellow Emperor was also very clever, or that it was possibly one of the emperor’s courtiers, also said to be quite clever. And some say that Cāngjié actually lived many years earlier than the Yellow Emperor (but was clever anyway).
But almost everyone agrees that Cāngjié had the head of a four-eyed dragon. People also say that even as a child, he loved to draw pictures. Sometimes he sat at the side of the river and noticed the markings on the backs of turtles. Or he would walk in the woods and note the patterns in the wings of birds. Or he would wander at night and note the arrangements of the stars. And he liked to draw all these things. Gradually, as he extracted the patterns, he found that he could rearrange them, assign them meanings, and manipulate them, until at last he was able to communicate with his drawings much as one could in speaking.
He taught other people his system, and thus writing was born. Cāngjié is honored to this day, of course, as the god of writing, and he is the special patron of book and paper makers, and of story tellers.