Taejo of Joseon (October 11, 1335 – May 24, 1408; r. 1392–1398), born Yi Seong-gye, whose changed name is Yi Dan, is the founder and the first king of the Joseon Dynasty of Korea, and the main figure in overthrowing the Goryeo Dynasty.

He is posthumously raised to the rank of Emperor in 1899 by Gojong, the Gwangmu Emperor, who had proclaimed the Korean Empire in 1897.

Taejo's father Yi Ja-chun was a minor Mongol official, but his ethnicity was Korean.

Taejo joins the Goryeo army and rises through the ranks, seizing the throne in 1392.

He abdicates in 1398 during the strife between his sons and dies in 1408.