Yi Ch'un (1265 – August 25, 1342[a]) or known for his Mongolian name Bayan Temür (Mongolian script: Баян төмөр; Pai-yen tö-mör) was the grandfather of Yi Sŏng-gye, founder of the Joseon Dynasty.
[1] From Yuan dynasty, he replaced his father, Yi Haeng-ni (이행리) as a chiliarch.
[2] He later married Lady Pak of the Munju Pak clan (문주 박씨; the future Queen Gyeongsun) and had 2 sons, they were: Yi Cha-hŭng and Yi Cha-ch'un, the biological father of Yi Sŏng-gye.
[citation needed] After Pak's death, Yi remarried again with Lady Cho (조씨), the daughter of Cho Yang-gi (조양기).
[3] In 5 August 1392, his grandson, Yi Sŏng-gye founded the Joseon Dynasty and he posthumously honoured his grandfather as King Gonguiseongdo the Great (공의성도대왕; 恭毅聖度大王) and gave him the temple name Dojo (도조; 度祖).