Year 1180 (MCLXXX) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar. Events By place Byzantine Empire September 24 – Emperor Manuel I (Komnenos) dies after a 37-year reign at Constantinople. He is succeeded by his 11-year-old son Alexios II – who will reign briefly as ruler of the Byzantine Empire with his mother, Maria of Antioch as regent (until 1183). Maria takes as her advisor and lover, Alexios Komnenos, a nephew of Manuel, causing a scandal among the Byzantine population. Europe January 13 – Henry the Lion, duke of Saxony, loses his Saxon and Bavarian duchies and all his imperial fiefs at an Imperial Diet in Würzburg for having breached the king's peace. Emperor Frederick I (Barbarossa) issues the Gelnhausen Charter on April 13. He breaks up Henry's former domain; one part of Saxony is renamed the Duchy of Westphalia, and other parts are given to his ally Otto I (the Redhead), duke of Bavaria. September 18 – King Louis VII (the Younger) dies after a 43-year reign at Paris. He is succeeded by his 15-year-old son Philip II, who becomes sole ruler of France (until 1223). The Portuguese admiral D. Fuas Roupinho wins a second victory in two years, against the Almohad fleet. The assembly traditionally regarded as the first Sejm of the Kingdom of Poland convenes at Łęczyca (approximate date). England Portsmouth is founded by the Norman merchant Jean de Gisors, establishing a trade route between England and France (approximate date). Levant Summer – King Baldwin IV (the Leper) sends messengers to Saladin with proposals of a peace treaty. Because of a terrible drought, the whole of Syria is faced with famine. Saladin agrees to a two-year truce. Raymond of Tripoli denounces the truce, but is compelled to accept it after an Ayyubid fleet raids the port of Tartus. Saladin intervenes in a quarrel between the Zangids of Mosul and the Artuqids. He convinces the Seljuks of the Sultanate of Rum not to interfere and raids Cilician Armenia. Baldwin IV marries his sister Sibylla to Guy of Lusignan, brother of the constable Amalric of Lusignan, and enfeoffed him with the County of Jaffa and Ascalon. Asia March 18 – Emperor Takakura is forced to abdicate by Taira no Kiyomori after a 12-year reign. He is succeeded by his 2-year-old son Antoku as emperor of Japan (until 1185). Kiyomori rules