Mortimer, R.de (English spelling) MortimerRde

Japanese: Mortimer，R.de（英語表記）MortimerRde

…After his accession to the throne, he allowed his favorite nobles to govern due to his innate weakness of character, and he was defeated in a war with Scotland, leading to a series of unrest. In his later years, he was driven from the throne by Queen Isabella and the nobleman Roger de Mortimer (1326), and was assassinated at Berkeley Castle the following year. [Ikuo Sato] …

From Edward III

…reigned from 1327 to 1377. He ascended to the throne the year after his father, Edward II, was deposed, but the real power in politics lay with his mother, Queen Isabella (daughter of Philip IV of France), and her favorite, Roger de Mortimer. In 1330, the king executed Mortimer and imprisoned the queen mother, seizing real power in the government. …

*Some of the terminology references "Mortimer, R.de" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…即位ののちは生来の性格の弱さもあって寵臣の貴族による政治を許したり，スコットランドとの戦いに敗れるなど，不穏な情勢が続いた。晩年は王后イザベラと貴族モーティマーRoger de Mortimerらによって王位を追われ(1326)，翌年バークリー城で暗殺された。【佐藤伊久男】。…