Question: What is the name of the elder brother emperor that signed the Truce of Ratisbon?
Context: Yuan Xie (元勰) (died 508), né Tuoba Xie (拓拔勰, changed 496), courtesy name Yanhe (彥和), formally Prince Wuxuan of Pengcheng (彭城武宣王), later posthumously honored as Emperor Wenmu (文穆皇帝) with the temple name of Suzu (肅祖), was an imperial prince of the Chinese/Xianbei dynasty Northern Wei.  He was a son of Emperor Xianwen, and he often assisted his brother Emperor Xiaowen both in military and governmental matters.  After Emperor Xiaowen's death, he briefly served as regent for Emperor Xiaowen's son Emperor Xuanwu.  Eventually, due to suspicions and jealousy of Emperor Xuanwu's uncle Gao Zhao, Emperor Xuanwu believed false reports that Yuan Xie was going to rebel, and forced him to commit suicide.  He was later posthumously honored as an emperor by his son Emperor Xiaozhuang, although subsequently Emperor Jiemin retracted the honors. Leopold I (name in full: "Leopold Ignaz Joseph Balthasar Felician"; Hungarian: "I. Lipót" ; 9 June 1640 – 5 May 1705) was Holy Roman Emperor, King of Hungary, Croatia, and Bohemia.  The second son of Ferdinand III, Holy Roman Emperor, by his first wife, Maria Anna of Spain, Leopold became heir apparent in 1654 by the death of his elder brother Ferdinand IV.  Elected in 1658, Leopold ruled the Holy Roman Empire until his death in 1705. Shahzada Mirza Muhammad Hakim (29 April 1553 – 10 October 1585), sometimes known simply as Mirza Hakim, short: Mirza, was the second son of Mughal emperor Humayun.  He ruled Kabul in Afghanistan, and often conflicted with his elder brother emperor Akbar.  Mirza Hakim later on mended ways with Emperor Akbar.  He is the son of Mah Chuchak Begum.  He is known for writing Tajdar-e-Haram(King of the Sanctuary) The Truce of Ratisbon, or Truce of Regensburg, concluded the War of the Reunions between Spain and France.  The Truce was signed on 15 August 1684 at the Dominican convent at Ratisbon in Bavaria between Louis XIV of France on the one side, and the Holy Roman Emperor, Leopold I, and the Spanish King, Charles II, on the other.  The final agreements allowed King Louis to retain Strasbourg, Luxembourg, and other Reunion gains, and Kortrijk and Diksmuide, both now in Belgium, were returned to Spain.  It was not, however, a definitive peace but only a truce for 20 years. Emperor Gong of Western Wei ((西)魏恭帝) (537–557), personal name né Yuan Kuo (元廓), later changed to Tuoba Kuo (拓拔廓), was the last emperor of the Western Wei -- a rump state of and successor to Northern Wei.  He was made emperor in 554 after his older brother Emperor Fei was deposed by the paramount general Yuwen Tai.  He carried little actual power, and in 556, after Yuwen Tai's death, Yuwen Tai's nephew Yuwen Hu, serving as guardian to Yuwen Tai's son Yuwen Jue, forced Emperor Gong to yield the throne to Yuwen Jue, ending Western Wei and starting Northern Zhou.  The former emperor was killed in 557.  Because Northern Wei's other branch successor state, Eastern Wei, had fallen in 550, Emperor Gong can be regarded as Northern Wei's final emperor as well. Yelü Lihu (耶律李胡) (911-960), also named Honggu (洪古), courtesy name Xiyin (奚隱), formally Emperor Zhangsu (章肅皇帝), was an imperial prince of the Khitan Liao state.  As the third son of Liao's founding emperor Emperor Taizu (Yelü Abaoji) and his wife Empress Shulü Ping, Yelü Lihu served as crown prince during the reign of his older brother Emperor Taizong (Yelü Deguang), who was their second son, as Empress Shulü wanted him to be emperor after Emperor Taizong.  However, after Emperor Taizong's death, their older brother Yelü Bei's son Yelü Ruan was able to defeat Yelü Lihu in battle and take the throne.  Yelü Lihu was put under arrest and later died while under arrest. Albert VI (German: "Albrecht VI."  ; 18 December 1418 – 2 December 1463), a member of the House of Habsburg, was Duke of Austria from 1424, elevated to Archduke in 1453.  As a scion of the Leopoldian line, he ruled over the Inner Austrian duchies of Styria, Carinthia and Carniola from 1424, from 1457 also over the Archduchy of Austria until his death, rivalling with his elder brother Emperor Frederick III.  According to tradition, Albert, later known as "the Prodigal", was the exact opposite of Frederick: energetic and inclined to thoughtlessness. Emperor Ming of Northern Zhou ((北)周明帝) (534–560), personal name Yuwen Yu (宇文毓), nickname Tongwantu (統萬突), was an emperor of the Xianbei dynasty Northern Zhou, although at the start of his reign he used the alternative title "Heavenly Prince" ("Tian Wang").  He was made emperor after his younger brother Emperor Xiaomin was deposed and killed by the regent Yuwen Hu.  Emperor Ming himself assumed some, but not all, powers from Yuwen Hu, and was generally considered able.  Because of this, Yuwen Hu became apprehensive, and in 560, he poisoned Emperor Ming to death.  While near death, however, Emperor Ming appointed his brother Yuwen Yong (Emperor Wu) as his successor, believing Yuwen Yong to be intelligent and capable, and in 572, Yuwen Yong was finally able to kill Yuwen Hu and assume full imperial powers. Emperor Wenzong of Tang (809–840), personal name Li Ang, né Li Han (李涵), was an emperor of the Tang dynasty of China.  He reigned from 827 to 840.  Emperor Wenzong was the second son of Emperor Muzong and younger brother of Emperor Jingzong.  A rare occurrence in Chinese history, Emperor Wenzong, along with his elder brother Emperor Jingzong and younger brother Emperor Wuzong, reigned in succession. Emperor Yuan of Liang () (508–555), personal name Xiao Yi (蕭繹), courtesy name Shicheng (世誠), nickname Qifu (七符), was an emperor of the Chinese Liang Dynasty.  After his father Emperor Wu and brother Emperor Jianwen were successively taken hostage and controlled by the rebel general Hou Jing, Xiao Yi was largely viewed as the "de facto" leader of Liang, and after defeating Hou in 552 declared himself emperor.  In 554, after offending Yuwen Tai, the paramount general of rival Western Wei, Western Wei forces descended on and captured his capital Jiangling (江陵, in modern Jingzhou, Hubei), executing him and instead declaring his nephew Xiao Cha (Emperor Xuan) the Emperor of Liang.
Answer: Ferdinand IV