Analysis of information sources in references of the Wikipedia article "House of Yi" in English language version.
朝野皆知新皇帝不慧,且無嗣屬望,……嚴貴妃方專寵,欲貴其子,厚賂博文,冀得其力;義親王堈,年雖長,多失儀、無人望,且孤立援少……由是衆議自歸於垠,援定宗朝故事,立爲皇太子。 (The people by the time knew that the new emperor was not exactly smart and there's no hope for him to produce an heir,... Lady Eom, the Imperial Noble Consort just gained much love from the Emperor [Emeritus] and she wanted to promote her son's position, so she bribed Itō Hirobumi for his support; the Prince Imperial Ui, despite being elder, had many scandals and lost reputation, making him lack to support... and so, people eventually agreed to make Yi Un the crown prince, following the precedent from King Jeongjong of Joseon.)《매천야록》卷之五·隆熙元年丁未第2條
His Majesty the Emperor of Japan will accord to their Majesties the Emperor and ex-Emperor and His Imperial Highness the Crown Prince of Korea and their consorts and heirs such titles, dignity, and honor as are appropriate to their respective ranks, and sufficient annual grants will be made for the maintenance of such titles, dignity and honor.
前韓國皇帝ヲ册シテ王ト爲シ昌德宮李王ト稱シ……皇太子及將來ノ世嗣ヲ王世子トシ太皇帝ヲ太王ト爲シ德壽宮李太王ト稱シ……
[Article 14]……Peers and peerage shall not be recognized.