Simplify the following text for a Grade 9 native English-speaking person.
Original: Heungseon Daewongun ( í ì ë ì ê , 1820 - 1898 ) or The Daewongun ( ë ì ê ) , or formally Heungseon Heonui Daewonwang ( í ì í -- ì ë ì ì ) and also known to period western diplomats as Prince Gung , was the title of Yi Ha-eung , regent of Joseon during the minority of King Gojong in the 1860s and until his death a key political figure of late Joseon Korea .
Simplified: Heungseon Daewongun or Daewon King of Heungseon ( Hangul : í ì ë ì ê , Hanja : è å # å é cents å , December 21 1820 - February 22 1898 ) was Choesens Poliltiker . regent of Joseon ( 1863 - 1874 ) was King Gojongs .