1. Yi Un was the 28th Head of the Korean Imperial House, an Imperial Japanese Army general and the last Imperial Crown Prince of the Korean Empire.

1. Yi Un was the 28th Head of the Korean Imperial House, an Imperial Japanese Army general and the last Imperial Crown Prince of the Korean Empire.
In 1910, the Korean Empire was annexed by Japan and Emperor Sunjong was forced to abdicate, and Yi Un married Princess Masako of Nashimoto, the eldest daughter of Prince Nashimoto Morimasa, on 28 April 1920 at Tokyo.
On 10 June 1926, upon the death of Emperor Sunjong, Yi Un received the late emperor's title, and became the King Yi of Changdeokgung, which referred to the palace Changdeokgung.
Yi Un achieved the rank of Lieutenant General in the Imperial Japanese Army, commanded Japanese forces in China and served as a member of the Supreme War Council.
Yi Un's mother was the Honorable Princess Consort Eom Seon-yeong, a palace attendant, who was posthumously awarded the title of Princess Sunheon.
Yi Un was the younger half-brother of Emperor Sunjong and Prince Imperial Ui.
Yi Un was titled Prince Imperial Yeong in 1900, and became the crown prince in 1907, despite being younger than Prince Ui.
Japanese Emperor Meiji, who largely ignored his own grandchildren, devoted a lot of attention to Yi Un, acting as his guardian.
Yi Un was allowed to visit Korea again only after the death of his mother in 1911.
Yi Un was poor in gymnastics due to his small stature, but excelled in music and martial arts.
Yi Un was then enrolled in the 29th class of the Imperial Japanese Army Academy, from which he graduated on 25 May 1917 with an excellent record.
Yi Un graduated from the 35th class of the Army Staff College in November 1923 and commanded a battalion of the Guards 2nd Infantry Regiment.
Yi Un was assigned to the Imperial Japanese Army General Staff Office in December 1924, and to the staff of the Chosen Army in July 1926.
Yi Un became colonel in August 1935 and commanded the Utsunomiya-based IJA 59th Infantry Regiment.
Yi Un was declared stateless, as Korea had become independent of the Empire of Japan, but Korean President Syngman Rhee had refused his request to be allowed to return to Korea with his family.
Yi Un returned to Japan in May In 1960, President Rhee again denied him permission to return to Korea, but instead offered the prince the position of Korean Ambassador to the Court of St James's.
Yi Un refused on the grounds of illness, but made a trip to New York from June to August 1960, and to Hawaii from March to May 1961.
Yi Un received treatment at St Mary's Hospital in Seoul.
Yi Un was buried at Hongreung in Namyangju, near Seoul.
Yi Un is known posthumously as Yi Un, Crown Prince Euimin of Korea.