Trajan is one of the most accomplished and esteemed emperors in the history of Rome. His reign marks the height of Roman territorial expansion. During his reign, Roman territory stretched from modern-day Portugal to modern-day Syria and Arabia — controlling the entirety of the Mediterranean, North Africa, western and central Europe, and the Near East.

Hadrian’s Wall was built during the reign of Emperor Hadrian (construction began circa 120 CE). The wall marked the northernmost boundary of the Roman Empire in the British Isles and was constructed to deter barbarian invasions from modern-day Scotland.

Historians consider Nero one of the most notorious of the Roman emperors. His rule is marked by several violent and questionable acts. The other answers are incorrect, as historians rank them as some of Rome's greatest emperors.

Nero was considered one of the most corrupt emperors to rule over the Romans and he was - according to popular legend- personally responsible for the Great Fire, so he would be the best choice. Marcus Aurelius lived about a century after the Great Fire, so he would not be a good choice. Caligula is an emperor remembered for excesses, however he lived before the Great Fire, so he too would not be a good answer. Lastly, Romulus is the largely mythological founder of Rome, so he would not be a good choice.

The fire happened under Nero's reign in 64 CE. We can start by ruling out the options that are BCE. The Fire of Rome happened in the later years of the Early Roman Empire. When we look in the common era, it can be tricky to choose between 64 and 124 CE. It's key to remember the fire happened early enough in this era to restart the Roman Empire. 

The Roman pantheon was destroyed in a devastating fire in 80 CE. It was later rebuilt and completed during the reign of Hadrian in 128 CE. The Roman pantheon was a large temple to the Roman Gods. It was first built by Marcus Agrippa, during the reign of Augustus Caesar.

The Great Fire of Rome took place in 64 CE, during the reign of Emperor Nero. There are many different historical accounts of the incident, with many primary sources claiming that Nero himself gave orders for the fire to be started. Nero, for his part, denied responsibility and blamed the fire on Rome’s Christian community. This led to a widespread persecution of Christians in the Roman Empire.

Rome initially viewed Christianity as a heretical religion and a minor threat to Roman society, but the Roman Empire at the time was vast and there were many heretical sects springing up all over the place. As Christianity grew rapidly in the first century, it began to attract more and more attention. By the reign of Nero, there were many Christians living in the city of Rome, and religious and ethnic tensions were growing. After the Great Fire of Rome in 64 CE, Nero tapped into this anti-Christian feeling and blamed the Christian population for deliberately and malevolently starting the fire. This led to a prolonged campaign of persecution against Rome’s Christian population.

The Great Fire of Rome took place in 64 CE and ravaged the city. Emperor Nero, who was widely disliked and distrusted by the Roman people, found himself being blamed for the fire, and so, attempted to turn this attention on to Rome’s Christian community. Nero publically blamed Christians for starting the fire and began a campaign of persecution against the Christian population.

Titus was the second emperor of the Flavian Dynasty. Although he ruled briefly, from 79 to 81 CE, his rule is important because it coincided with the eruption of Mount Vesuvius and a terrible fire in Rome. Titus was remembered fondly by the Romans for leading the disaster relief campaign in the wake of these two catastrophes.