Question: In which battle the Roman Emperor from 361 to 363 was killed?

full_context: Document 1: Byzantine–Sasanian War of 602–628: The Byzantine–Sasanian War of 602–628 was the final and most devastating of the series of wars fought between the Byzantine (Eastern Roman) Empire and the Sasanian Empire of Persia. The previous war between the two powers had ended in 591 after Emperor Maurice helped the Sasanian king Khosrow II regain his throne. In 602 Maurice was murdered by his political rival Phocas. Khosrow proceeded to declare war, ostensibly to avenge the death of Maurice. This became a decades-long conflict, the longest war in the series, and was fought throughout the Middle East: in Egypt, the Levant, Mesopotamia, the Caucasus, Anatolia, Armenia, the Aegean Sea and even before the walls of Constantinople itself.
Document 2: Julian (emperor): Julian (Latin: "Flavius Claudius Iulianus Augustus" ; Greek: Φλάβιος Κλαύδιος Ἰουλιανὸς Αὔγουστος ; 331/332  – 26 June 363), also known as Julian the Apostate, was Roman Emperor from 361 to 363, as well as a notable philosopher and author in Greek.
Document 3: Oribasius: Oribasius or Oreibasius (Greek: Ὀρειβάσιος ; c. 320 – 403) was a Greek medical writer and the personal physician of the Roman emperor Julian the Apostate. He studied at Alexandria under physician Zeno of Cyprus before joining Julian's retinue. He was involved in Julian's coronation in 361, and remained with the emperor until Julian's death in 363. In the wake of this event, Oribasius was banished to foreign courts for a time, but was later recalled by the emperor Valens.
Document 4: Battle of Ctesiphon (363): The Battle of Ctesiphon took place on May 29, 363 between the armies of Roman Emperor Julian and an army of the Sasanian Empire (during Shapur II's reign) outside the walls of the Persian capital Ctesiphon. The battle was a Roman victory, although Julian was killed following the subsequent Battle of Samarra and the Roman forces found themselves unable to continue their campaign as they were too far from their supply lines.
Document 5: Julius Africanus: Julius Africanus was a celebrated orator in the reign of Nero, and seems to have been the son of the Julius Africanus, of the Gallic state of the Santoni, who was condemned by Tiberius in 32 AD. Quintilian, who had heard Julius Africanus, spoke of him and Domitius Afer as the best orators of their time. The eloquence of Africanus was chiefly characterized by vehemence and energy. Pliny the Younger mentions a grandson of this Julius Africanus, who was also an advocate and was opposed to him upon one occasion. He was consul suffectus in 108 AD.
Document 6: Against the Galilaeans: Against the Galilaeans (Ancient Greek: Κατὰ Γαλιλαίων ; Latin: "Contra Galilaeos" ), meaning Christians, was a Greek polemical essay written by the Roman Emperor Flavius Claudius Julianus, commonly known as Julian the Apostate, during his short reign (361–363). Despite having been originally written in Greek, it is better known under its Latin name, probably due to its extensive reference in the polemical response "Contra Julianum" by Cyril of Alexandria.
Document 7: Battle of Maranga: The Battle of Maranga occurred in 363 AD, shortly after the Battle of Ctesiphon. The Romans repelled a Sasanian attack while sustaining minimal losses. However, the army's lack of supplies continued to threaten the army, and soon afterwards the emperor Julian was killed at the Battle of Samarra.
Document 8: Constantine the Great: Constantine the Great (Latin: "Flavius Valerius Aurelius Constantinus Augustus" ; Greek: Κωνσταντῖνος ὁ Μέγας ; 27 February 272 AD – 22 May 337 AD), also known as Constantine I or Saint Constantine (in the Orthodox Church as Saint Constantine the Great, Equal-to-the-Apostles), was a Roman Emperor of Illyrian-Greek origin from 306 to 337 AD. He was the son of Flavius Valerius Constantius, a Roman Army officer, and his consort Helena. His father became "Caesar", the deputy emperor in the west, in 293 AD. Constantine was sent east, where he rose through the ranks to become a military tribune under Emperors Diocletian and Galerius. In 305, Constantius raised himself to the rank of "Augustus", senior western emperor, and Constantine was recalled west to campaign under his father in Britannia (Britain). Constantine was acclaimed as emperor by the army at Eboracum (modern-day York) after his father's death in 306 AD, and he emerged victorious in a series of civil wars against Emperors Maxentius and Licinius to become sole ruler of both west and east by 324 AD.
Document 9: Anarchy at Samarra: The term "Anarchy at Samarra" refers to the period 861–870 in the history of the Abbasid Caliphate, which was marked by extreme internal instability and the violent succession of four caliphs, who became puppets in the hands of powerful rival military groups. The term derives from the then capital and seat of the caliphal court, Samarra. The "anarchy" began in 861, with the murder of Caliph al-Mutawakkil by his Turkish guards. His successor, al-Muntasir, ruled for six months before his death, possibly poisoned by the Turkish military chiefs. He was succeeded by al-Musta'in. Divisions within the Turkish military leadership enabled Musta'in to flee to Baghdad in 865 with the support of some Turkish chiefs (Bugha the Younger and Wasif) and the Tahirids, but the rest of the Turkish army chose a new caliph in the person of al-Mu'tazz and besieged Baghdad, forcing the city's capitulation in 866. Musta'in was exiled and executed. Mu'tazz was able and energetic, and tried to control the military chiefs and exclude the military from civil administration. His policies were resisted, and in July 869 he too was deposed and killed. His successor, al-Muhtadi, also tried to reaffirm the Caliph's authority, but he too was killed in June 870. With Muhtadi's death and the ascension of al-Mu'tamid, the Turkish faction around Musa ibn Bugha, closely associated with Mu'tamid's brother and regent al-Muwaffaq, became dominant in the caliphal court, ending the "anarchy". Although the Abbasid Caliphate was able to stage a modest recovery in the following decades, the troubles of the "Anarchy at Samarra" inflicted great and lasting damage on the structures and prestige of the Abbasid central government, encouraging and facilitating secessionist and rebellious tendencies in the Caliphate's provinces.
Document 10: Dagalaifus (Roman Consul, 366): Dagalaifus was a pagan of Germanic descent. In the year 361, he was appointed by Emperor Julian as comes domesticorum (Commander of the Household Guard). He accompanied Julian on his march through Illyricum to quell what remained of the government of Constantius II that year. He led a party into Sirmium that arrested the commander of the resisting army, Lucillianus. In the spring of 363, Dagalaifus was part of Julian’s ultimately-disastrous invasion of Persia. On June 26, while still campaigning, Julian was killed in a skirmish. Dagalaifus, who had been with the rear guard, played an important role in the election of the next emperor. The council of military officers (including Dagalaifus) finally agreed on the new "comes domesticorum", Jovian, to succeed Julian. Jovian was a Christian whose father Varronianus had himself once served as "comes domesticorm".
Document 11: Julian's Persian War: Julian's Persian War, or the Perso-Roman War of 363, was the last undertaking of the Roman emperor Julian, begun in March 363. It was an aggressive war against the Persian Empire ruled by the Sassanian king Shapur II. Shapur is believed to have expected an invasion by way of the Tigris valley. Julian sent a detachment to join with his ally Arshak II of Armenia and take the Tigris route. Meanwhile, with his main army he advanced rapidly down the Euphrates valley, meeting only scattered opposition, and reached the walls of the Persian capital Ctesiphon where he met and defeated the Persian army at the Battle of Ctesiphon (363). Unable to take the city, and with a faltering plan of campaign, He was misled by Persian spies into burning his fleet and taking a disadvantageous route of retreat in which his army was constantly harassed and his progress crawled to a halt.
Document 12: Constantius II: Constantius II (Latin: "Flavius Julius Constantius Augustus" ; 7 August 317 – 3 November 361) was Roman Emperor from 337 to 361. The second son of Constantine I and Fausta, he ascended to the throne with his brothers Constantine II and Constans upon their father's death.
Document 13: Battle of Carrhae: The Battle of Carrhae ] was fought in 53 BC between the Roman Republic and the Parthian Empire near the town of Carrhae. The Parthian Spahbod ("General") Surena decisively defeated a numerically superior Roman invasion force under the command of Marcus Licinius Crassus. It is commonly seen as one of the earliest and most important battles between the Roman and Parthian empires and one of the most crushing defeats in Roman history.
Document 14: Eutropius (historian): Flavius Eutropius was an Ancient Roman historian who flourished in the latter half of the 4th century AD. He held the office of secretary ("magister memoriae") at Constantinople, accompanied the Emperor Julian (361–363) on his expedition against the Persians (363), and was alive during the reign of Valens (364–378), to whom he dedicates his "Breviarium historiae Romanae" and where his history ends. Possibly he held higher state offices in later years, becoming Praetorian prefect for Illyria in 380 and - together with emperor Valentinian II - consul in 387. However, it is a question of academic discussion whether the Eutropius holding these offices is really to be identified with the historian.
Document 15: Surena: Surena or Suren or Sourena (died 53 BC) was a Parthian spahbed ("General" or "Commander") during the 1st century BC. He was a member of the House of Suren and was best known for defeating the Romans in the Battle of Carrhae. Under his command Parthians decisively defeated a numerically superior Roman invasion force under the command of Marcus Licinius Crassus. It is commonly seen as one of the earliest and most important battles between the Roman and Parthian empires and one of the most crushing defeats in Roman history.
ground_truth: Battle of Samarra