In East Zhou dynasty Chinese had already the custom of worshipping Gate Gods. At that time, the worship was one of the most important Chinese New Year worships. The emperor led a grand Gate God worship for the whole nation every year. The ministers and other people held their own family worships at home. But the custom changed gradually. Today Gate God worhship is quiet simple, that is, the people put on new pictures or names of the Gate Gods short before Chinese New Year.
The God figures have also changed much during the past three thousands of year. Before Tang dynasty, the Gate Gods are Yu and Lei, the original Gate Gods. Yu and Lei are two figures in Chinese mythology. It is said that Yu and Lei have very sensitive noses. Every morning they stand beside the hell gate and check with their noses if any ghost coming in the door has done evil thing to people. If they find a ghost who has done such thing, they feed it to tigers. All ghosts are afraid of them. In Tang dynasty, people created some new Gate Gods. Zhong Kui is one of the most popular Gate God figures created in middle Tang dynasty. According to Chinese mythology, Zhong Kui was a very ugly person, therefore the emperor didn't use him even though he took the first place in an imperial exam. Zhong Kui died of anger. In Hell, he is appointed to manage all the ghosts. He is honest and righteous, so all ghosts both respect and are afraid of him. He is uglier than any other ghost. This is also a reason that the ghosts are very afraid of him. Wei Chigong and Qin Qiong are also two Gate Gods created in Tang dynasty. Both of them were valiant generals. The famous emperor Li Shiming had sleep problem in a period because of fear. The sleep problem got healed after he asked for one of his generals guarding his bedroom. Later the people heard the story and created their own Gate Gods with the figures of the two mentioned heroes with big-names.
With time going on, more and more Gate Gods were created by the people. Both the characters and styles of the Gate Gods can be different in different regions. According to the Chinese native religion, Taoism, everyone can be a God if he/she has outstanding characters, such as kindness, intelligence, valiance, loyality, etc. and the people worship him/her voluntarily. This is the religious theory base of the producing of the new Gate Gods.