gojoseon is the first state in korean history. it was established in 2333 bce. its real name is joseon, but it is called gojoseon to make it different from other joseon in korean history. go is a korean prefix meaning 'old'. the founder of gojoseon is said to be dangun. the korean people believe that dangun established the country on october 3rd, and still celebrate that day. in korea, october 3rd is a national holiday, which is named gaecheonjeol (the day heaven opened). it is said to be the day that dangun's father whose name is hwan-ung came from the sky on october 3rd 2457 bce. gochosun was destroyed by the chinese han dynasty in 108 bce.