Treatise on Armament Technology, Volume 229

Records of Geographical Survey

Page 420; Sheet: 3

...the horses were brought directly up, and an order was given to provide for them. In the twenty-first year 1388 CE, the Chancellor Yi In-im deposed U King U of Goryeo and enthroned Chang King Chang. Within that year, they twice requested permission to attend the imperial court, but both requests were denied.

Yi Seong-gye subsequently deposed Chang and enthroned Yo, the Prince of Jeongchang-gun King Gongyang, the last ruler of Goryeo. Yo once sent his son, Seok, to attend the court. However, before Seok could return, Yi Seong-gye deposed Yo and established himself as ruler. The Wang family the royal house of Goryeo had ruled from the time of the Five Dynasties 907–979 CE until the present; after several hundred years, their state's line was severed.

The Council of State sent a memorial arguing that U and Chang should not have been enthroned this was a political justification claiming they were not of true royal blood. They claimed that Yo was tyrannical and had lost the hearts of the people, leaving the state vacant without a king. They argued there was no one more suitable than Yi Seong-gye to take the lead. They stated they would only follow what the Imperial Court commanded.

The Emperor Hongwu said: "They are merely foreigners; why should I punish them?" The Emperor expresses a policy of non-intervention in the internal coups of a vassal state.

Yi Seong-gye changed his name to Dan and moved the capital to Hanseong modern-day Seoul. Soon after, he requested a change to the national title. An imperial edict was issued decreeing that the country should henceforth be called Joseon a name referencing the ancient state of Gojoseon, meaning "Morning Calm".

In the twenty-eighth year 1395 CE, they arrived to offer tribute, but the language used in their formal memorial was considered disrespectful. The author of the memorial, Jeong Chong, was arrested and detained. An order was issued to Liaodong the Ming frontier province to sever relations with Joseon.

Later, as Yi Seong-gye grew old, he requested that his son Bang-won the future King Taejong be allowed to succeed him. In the first year of the Yongle reign 1403 CE, the Emperor bestowed upon him ceremonial robes, headwear, and the Classics—