Grand Prince Imyeong

Yi Gu (7 January 1420 – 21 January 1469 ), formally known as Grand Prince Imyeong, was an imperial prince of the Joseon dynasty. He was the fourth son of King Sejong. His brothers were King Munjong of Joseon and King Sejo of Joseon.

Biography
Yi Gu was born as the 4th son and 6th child of King Sejong and his wife, Queen Soheon.

From an early age, he was proud and kept a filial attitude to his parents and siblings. When he was a child, he was praised for being sincere. His father, King Sejong was very fond of him.

Like his second older brother, Grand Prince Suyang, he was proficient in martial arts, but he also created a scandal due to having sexual intercourse with court ladies and maids of the palace.

Yi Gu firstly married Princess Consort Nam, but after a month of marriage, their marriage became problematic. Despite the relationship, a son was born. But this led to the Grand Prince to marry Lady Choi of the Jeonju Choi clan, later being titled as Princess Consort Jean, as his second wife and later marry Princess Consort Ahn of the Andong Ahn clan as his third wife. Both marriages produced 5 daughters and 8 sons. He also had a concubine but no issue was born from the relationship.

In 1440, at the age of 20, the Grand Prince became the Yeonguijeong.

During the Gyeyujeong Rebellion, when Grand Prince Suyang fought for the throne against their nephew, King Danjong, Yi Gu supported and helped Grand Prince Suyang. Prince Imyeong greatly assisted Grand Prince Suyang and contributed to the enthronement of his brother as King Sejo in 1453.

Yi Gu died on January 21, 1469. He was buried in Gyeonggi-do Uiwang-si.

Family
Parents


 * Father: Sejong the Great of Joseon (15 May 1397 – 8 April 1450)
 * Mother: Queen Soheon of the Cheongsong Sim clan (12 October 1395 – 19 April 1446)
 * Older sister: Princess Jeongso (1412–1424)
 * Older brother: Yi Hyang, King Munjong (15 November 1414 – 1 June 1452)
 * Older sister: Princess Jeongui (1415 – 11 February 1477)
 * Older brother: Yi Yu, King Sejo (2 November 1417 – 23 September 1468)
 * Older brother: Yi Yong, Grand Prince Anpyeong (18 October 1418 – 18 November 1453)
 * Younger brother: Yi Yeo, Grand Prince Gwangpyeong (2 May 1425 – 7 December 1444)
 * Younger brother: Yi Yu, Grand Prince Geumseong (5 May 1426 – 7 November 1457)
 * Younger brother: Yi Im, Grand Prince Pyeongwon (18 November 1427 – 16 January 1445)
 * Younger brother: Yi Yeom, Grand Prince Yeongeung (23 May 1434 – 2 February 1467)

Consort and issues:


 * Princess Consort Nam of the Uiryeong Nam clan (1426–?); second daughter of Nam Ji (남지, 南智; 1392–1454)
 * Eighth Son: Yi Tak, Prince Yunsan (1461–1547)
 * Princess Consort Jean of the Jeonju Choi clan (1420–?); daughter of Choi Seung-ryeong (최승령, 崔承寧; 1405–1445)
 * First Daughter: Princess Jungmo (1435–?)
 * First Son: Yi Ju, Prince Ohsan (1437–1489)
 * Second Son: Yi Jun, Prince Gwiseong (20 January 1441 – 28 January 1479)
 * Second Daughter: Princess Cheongha (1445–?)
 * Third Son: Yi Sun, Prince Jeongyang (1453–1492)
 * Fourth Son: Yi Jeong, Prince Palgye (1454–?)
 * Fifth Son: Yi Jing, Prince Hwanseong (1456–?)
 * Princess Consort Ahn of the Andong Ahn clan (1422–?)
 * Third Daughter: Princess Yi of the Jeonju Yi clan (1456–?)
 * Sixth Son: Yi Ham, Prince Yeongyang (1458–1526)
 * Fourth Daughter: Princess Yi of the Jeonju Yi clan (1458–?)
 * Seventh Son: Yi Rin, Dangyebujeong (1460–1521)
 * Ninth Son: Yi Ok, Prince Okcheon (1464–?)
 * Fifth Daughter: Princess Yi of the Jeonju Yi clan (1466–?)
 * Concubine Geum Gang-mae (1430–?)