Since the Korean peninsula was under the tributary system from the Goryeo period which was subjected to the interference by the Mongolian Empire to Joseon Dynasty, the successor to the king was called '王世子 (crown prince)', but since the Treaty of Shimonoseki was concluded as a result of Sino-Japanese War, Korea was released from the tributary system of the Qing,, the name of the country was changed to Korea and 'Crown Prince' came into use.
朝鮮半島においては、高麗のモンゴル帝国干渉期から李氏朝鮮まで他国の冊封体制下にあったため太子の称号が使えず、国王の継承者は「王世子」と呼ばれていたが、日清戦争の結果、下関条約が結ばれた事により清国の冊封から外れ、国号を大韓と改めた際に「皇太子」を使うようになった。