The origin of Chang can be traced to the ancient times of Huangdi. According to legend, Huandi's 5th son's descendent, Hui, invented the bow and arrow. Hence, Huangdi conferred on him the title of Gong Zhen (title of an official post). Gong Zhen was also known as Gong Chang. When the characters Gong and Chang were put together, they made up the character Chang ??
During the Spring-Autumn period, there was a noble from the Jin Kingdom whose name was Jiezhang(1). His descendents commemorated him by partially adopting his name as their surname.