Question: When did the emperor who forced the Germanic tribes to the east side of the Rhine die?

full_context: Document 1: Galicia (Spain): In the early 5th century, the deep crisis suffered by the Roman Empire allowed different tribes of Central Europe (Suebi, Vandals and Alani) to cross the Rhine and penetrate into the rule on 31 December 406. Its progress towards the Iberian Peninsula forced the Roman authorities to establish a treaty (foedus) by which the Suebi would settle peacefully and govern Galicia as imperial allies. So, from 409 Galicia was taken by the Suebi, forming the first medieval kingdom to be created in Europe, in 411, even before the fall of the Roman Empire, being also the first Germanic kingdom to mint coinage in Roman lands. During this period a Briton colony and bishopric (see Mailoc) was established in Northern Galicia (Britonia), probably as foederati and allies of the Suebi. In 585, the Visigothic King Leovigild invaded the Suebic kingdom of Galicia and defeated it, bringing it under Visigoth control.
Document 2: Utrecht: From the middle of the 3rd century Germanic tribes regularly invaded the Roman territories. Around 275 the Romans could no longer maintain the northern border and Utrecht was abandoned. Little is known about the next period 270–650. Utrecht is first spoken of again several centuries after the Romans left. Under the influence of the growing realms of the Franks, during Dagobert I's reign in the 7th century, a church was built within the walls of the Roman fortress. In ongoing border conflicts with the Frisians this first church was destroyed.
Document 3: Roman Republic: Beginning in the summer of 54 BC, a wave of political corruption and violence swept Rome. This chaos reached a climax in January of 52 BC, when Clodius was murdered in a gang war by Milo. On 1 January 49 BC, an agent of Caesar presented an ultimatum to the senate. The ultimatum was rejected, and the senate then passed a resolution which declared that if Caesar did not lay down his arms by July of that year, he would be considered an enemy of the Republic. Meanwhile, the senators adopted Pompey as their new champion against Caesar. On 7 January of 49 BC, the senate passed a senatus consultum ultimum, which vested Pompey with dictatorial powers. Pompey's army, however, was composed largely of untested conscripts. On 10 January, Caesar crossed the Rubicon with his veteran army (in violation of Roman laws) and marched towards Rome. Caesar's rapid advance forced Pompey, the consuls and the senate to abandon Rome for Greece. Caesar entered the city unopposed.
Document 4: Germans: Conflict between the Germanic tribes and the forces of Rome under Julius Caesar forced major Germanic tribes to retreat to the east bank of the Rhine. Roman emperor Augustus in 12 BC ordered the conquest of the Germans, but the catastrophic Roman defeat at the Battle of the Teutoburg Forest resulted in the Roman Empire abandoning its plans to completely conquer Germany. Germanic peoples in Roman territory were culturally Romanized, and although much of Germany remained free of direct Roman rule, Rome deeply influenced the development of German society, especially the adoption of Christianity by the Germans who obtained it from the Romans. In Roman-held territories with Germanic populations, the Germanic and Roman peoples intermarried, and Roman, Germanic, and Christian traditions intermingled. The adoption of Christianity would later become a major influence in the development of a common German identity.
Document 5: Switzerland: In about 260 AD, the fall of the Agri Decumates territory north of the Rhine transformed today's Switzerland into a frontier land of the Empire. Repeated raids by the Alamanni tribes provoked the ruin of the Roman towns and economy, forcing the population to find shelter near Roman fortresses, like the Castrum Rauracense near Augusta Raurica. The Empire built another line of defense at the north border (the so-called Donau-Iller-Rhine-Limes), but at the end of the fourth century the increased Germanic pressure forced the Romans to abandon the linear defence concept, and the Swiss plateau was finally open to the settlement of German tribes.
Document 6: Southern Europe: The Roman Empire came to dominate the entire Mediterranean basin in a vast empire based on Roman law and Roman legions. It promoted trade, tolerance, and Greek culture. By 300 AD the Roman Empire was divided into the Western Roman Empire based in Rome, and the Eastern Roman Empire based in Constantinople. The attacks of the Germanic peoples of northern Europe led to the Fall of the Western Roman Empire in AD 476, a date which traditionally marks the end of the classical period and the start of the Middle Ages.
Document 7: Assassination of Julius Caesar: Two days after the assassination, Mark Antony summoned the senate and managed to work out a compromise in which the assassins would not be punished for their acts, but all of Caesar's appointments would remain valid. By doing this, Antony most likely hoped to avoid large cracks in government forming as a result of Caesar's death. Simultaneously, Antony diminished the goals of the conspirators. The result unforeseen by the assassins was that Caesar's death precipitated the end of the Roman Republic. The Roman lower classes, with whom Caesar was popular, became enraged that a small group of aristocrats had sacrificed Caesar. Antony, who had been drifting apart from Caesar, capitalised on the grief of the Roman mob and threatened to unleash them on the Optimates, perhaps with the intent of taking control of Rome himself. But, to his surprise and chagrin, Caesar had named his grandnephew Gaius Octavius his sole heir, bequeathing him the immensely potent Caesar name as well as making him one of the wealthiest citizens in the Republic. Upon hearing of his adopted father's death, Octavius abandoned his studies in Apollonia and sailed across the Adriatic Sea to Brundisium. Octavius became Gaius Julius Caesar Octavianus or Octavian, the son of the great Caesar, and consequently also inherited the loyalty of much of the Roman populace. Octavian, aged only 18 at the time of Caesar's death, proved to have considerable political skills, and while Antony dealt with Decimus Brutus in the first round of the new civil wars, Octavian consolidated his tenuous position. Antony did not initially consider Octavius a true political threat due to his young age and inexperience, but Octavius quickly gained the support and admiration of Caesar's friends and supporters.
Document 8: Roman Republic: After the assassination, Mark Antony formed an alliance with Caesar's adopted son and great-nephew, Gaius Octavian. Along with Marcus Lepidus, they formed an alliance known as the Second Triumvirate. They held powers that were nearly identical to the powers that Caesar had held under his constitution. As such, the Senate and assemblies remained powerless, even after Caesar had been assassinated. The conspirators were then defeated at the Battle of Philippi in 42 BC. Eventually, however, Antony and Octavian fought against each other in one last battle. Antony was defeated in the naval Battle of Actium in 31 BC, and he committed suicide with his lover, Cleopatra. In 29 BC, Octavian returned to Rome as the unchallenged master of the Empire and later accepted the title of Augustus ("Exalted One"). He was convinced that only a single strong ruler could restore order in Rome.
Document 9: Roman Republic: Clodius formed armed gangs that terrorised the city and eventually began to attack Pompey's followers, who in response funded counter-gangs formed by Titus Annius Milo. The political alliance of the triumvirate was crumbling. Domitius Ahenobarbus ran for the consulship in 55 BC promising to take Caesar's command from him. Eventually, the triumvirate was renewed at Lucca. Pompey and Crassus were promised the consulship in 55 BC, and Caesar's term as governor was extended for five years. Crassus led an ill-fated expedition with legions led by his son, Caesar's lieutenant, against the Kingdom of Parthia. This resulted in his defeat and death at the Battle of Carrhae. Finally, Pompey's wife, Julia, who was Caesar's daughter, died in childbirth. This event severed the last remaining bond between Pompey and Caesar.
Document 10: Roman Republic: By 59 BC an unofficial political alliance known as the First Triumvirate was formed between Gaius Julius Caesar, Marcus Licinius Crassus, and Gnaeus Pompeius Magnus ("Pompey the Great") to share power and influence. In 53 BC, Crassus launched a Roman invasion of the Parthian Empire (modern Iraq and Iran). After initial successes, he marched his army deep into the desert; but here his army was cut off deep in enemy territory, surrounded and slaughtered at the Battle of Carrhae in which Crassus himself perished. The death of Crassus removed some of the balance in the Triumvirate and, consequently, Caesar and Pompey began to move apart. While Caesar was fighting in Gaul, Pompey proceeded with a legislative agenda for Rome that revealed that he was at best ambivalent towards Caesar and perhaps now covertly allied with Caesar's political enemies. In 51 BC, some Roman senators demanded that Caesar not be permitted to stand for consul unless he turned over control of his armies to the state, which would have left Caesar defenceless before his enemies. Caesar chose civil war over laying down his command and facing trial.
Document 11: Roman Republic: Caesar held both the dictatorship and the tribunate, and alternated between the consulship and the proconsulship. In 48 BC, Caesar was given permanent tribunician powers. This made his person sacrosanct, gave him the power to veto the senate, and allowed him to dominate the Plebeian Council. In 46 BC, Caesar was given censorial powers, which he used to fill the senate with his own partisans. Caesar then raised the membership of the Senate to 900. This robbed the senatorial aristocracy of its prestige, and made it increasingly subservient to him. While the assemblies continued to meet, he submitted all candidates to the assemblies for election, and all bills to the assemblies for enactment. Thus, the assemblies became powerless and were unable to oppose him.
Document 12: Imperialism: From their original homelands in Scandinavia and northern Europe, Germanic tribes expanded throughout northern and western Europe in the middle period of classical antiquity; southern Europe in late antiquity, conquering Celtic and other peoples; and by 800 CE, forming the Holy Roman Empire, the first German Empire. However, there was no real systemic continuity from the Western Roman Empire to its German successor which was famously described as "not holy, not Roman, and not an empire", as a great number of small states and principalities existed in the loosely autonomous confederation. Although by 1000 CE, the Germanic conquest of central, western, and southern Europe (west of and including Italy) was complete, excluding only Muslim Iberia. There was, however, little cultural integration or national identity, and "Germany" remained largely a conceptual term referring to an amorphous area of central Europe.
Document 13: Roman Republic: In 121 BC, Rome came into contact with two Celtic tribes (from a region in modern France), both of which they defeated with apparent ease. The Cimbrian War (113–101 BC) was a far more serious affair than the earlier clashes of 121 BC. The Germanic tribes of the Cimbri and the Teutons migrated from northern Europe into Rome's northern territories, and clashed with Rome and her allies. At the Battle of Aquae Sextiae and the Battle of Vercellae both tribes were virtually annihilated, which ended the threat.
Document 14: Roman Republic: Caesar was now the primary figure of the Roman state, enforcing and entrenching his powers. His enemies feared that he had ambitions to become an autocratic ruler. Arguing that the Roman Republic was in danger, a group of senators hatched a conspiracy and assassinated Caesar at a meeting of the Senate in March 44 BC.  Mark Antony, Caesar's lieutenant, condemned Caesar's assassination, and war broke out between the two factions. Antony was denounced as a public enemy, and Caesar's adopted son and chosen heir, Gaius Octavianus, was entrusted with the command of the war against him. At the Battle of Mutina Mark Antony was defeated by the consuls Hirtius and Pansa, who were both killed.
Document 15: Roman Britain: Julius Caesar invaded Britain in 55 and 54 BC as part of his Gallic Wars. The Britons had been overrun or culturally assimilated by other Celtic tribes during the British Iron Age and had been aiding Caesar's enemies. He received tribute, installed a friendly king over the Trinovantes, and returned to Gaul. Planned invasions under Augustus were called off in 34, 27, and 25 BC. In 40 AD, Caligula assembled 200,000 men at the Channel, only to have them gather seashells. Three years later, Claudius directed four legions to invade Britain and restore an exiled king over the Atrebates. The Romans defeated the Catuvellauni, and then organized their conquests as the Province of Britain (Latin: Provincia Britannia). By the year 47, the Romans held the lands southeast of the Fosse Way. Control over Wales was delayed by reverses and the effects of Boudica's uprising, but the Romans expanded steadily northward.
ground_truth: March 44 BC
sub_queries: What emperor forced the Germanic tribes to the east side of the Rhine? Answer: Julius Caesar
When did Julius Caesar die? Answer: March 44 BC