Most of Augustus' successors accepted his conservative and defensive foreign policy. Trajan was the first emperor to go on the offensive for an extended period of time. He crossed the Danube between 101 and 106 C.E. and created the new province of Dacia between the Danube and the Carpathian Mountains.

He was very doubt enticed by its gold mines, but he was also likely following a new overall strategy: to defend the empire more forcefully by pushing wedges into the territories of dangerous barbarians.

The invasion of the Parthian Empire in the East (113–117 C.E.) followed the same plan. Trajan's early success was astounding, and he founded three new provinces in Armenia, Assyria, and Mesopotamia. His lines, however, were overly long. Rebellions erupted.

Hadrian's reign saw a significant shift in Rome's border policy. Previously, Rome was on the attack against the barbarians. Despite the fact that the Romans seldom won additional land, they conducted regular attacks to punish and appease hostile tribes.

Hadrian fortified Roman fortifications by erecting a stone wall in southern Scotland and a timber wall across the Rhine-Danube triangle.

The Roman defense grew tight, and the initiative was taken up by the barbarians. Marcus Aurelius was forced to spend the majority of his reign repelling hazardous invasions in the East and along the Danube border.

The Roman Empire's civilisation was dependent on the health of its towns. The average city had roughly 20,000 people, and just three or four had a population of more than 75,000. The population of Rome, on the other hand, was unquestionably larger than 500,000, if not more than a million. People visiting Rome for the first time found it overwhelming, with its vastness, hustle, and noise delighting or horrifying them. The wealthy resided in opulent mansions known as domu_ s.

These were single-story buildings with lots of space, an open central courtyard, and rooms built for distinct and varied activities, such as dining, lounging, or sleeping, all in seclusion and relative silence. Despite the fact that only a tiny fraction of Rome's population resided in them, domu_ s took up a significant amount of space.

The Romans introduced the notion of the semicircular arch, taken from the Etruscans, to the fundamental post-and-lintel design employed by the Greeks. They also made extensive use of concrete, a building material invented by the Hellenistic Greeks and completely perfected by the Romans. The arch, together with the pillar and lintel, formed the foundation for the Flavian emperors' vast Colosseum.

The arch, when employed inside in the shape of vaults and domes, allowed for vast buildings such as baths, the most renowned and best preserved of which are those of the later emperors Caracalla (r. 211–217) and Diocletian (r. 284–305). (See Figs. 5–3.)

All of these characteristics were united in one of Rome's most iconic buildings, the Pantheon, which was begun by Augustus' friend Agrippa and renovated by Hadrian.

Magistrates and council members were held individually and collectively liable for unpaid taxes. Some magistrates even emigrated to evade their responsibilities, a behavior that grew common in succeeding decades.

These shortcomings mirrored more fundamental issues.

The affluence brought about by the end of civil war and the infusion of money from the East could not last beyond the first part of the second century C.E. Population likewise appears to have fallen for unknown causes.

The expense of government continued to rise. The emperors were compelled to maintain a permanent army, although a small one, in order to keep the people of Rome happy with "bread and circuses," to pay for an ever-expanding bureaucracy, and to undertake costly battles to protect the borders against invading armies.

Despite its origins among poor people in an obscure and isolated part of the empire, Christianity arose, expanded, and eventually conquered the Roman Empire. The traditional religious institutions of Judea were hostile to Christianity. It also had to contend with Rome's official cults and the extremely complex ideas of the educated classes, as well as other "mystery" religions like Mithra, Isis, and Osiris.

The Christians were also subjected to imperial official hostility and formal persecution. Nonetheless, Christianity gained toleration and, eventually, sole command as the empire's official religion.

He was impoverished, which raised eyebrows among the higher classes. His new message, as well as his criticism of religious activities associated with the temple in Jerusalem and its priests, incited the religious establishment's animosity.

Because of a misunderstanding of the movement, it was simple to persuade the Roman governor, Pontius Pilate, that Jesus and his disciples were dangerous revolutionaries. He was executed in Jerusalem, most likely around 30 C.E., via the harsh and demeaning procedure of crucifixion.

His disciples thought he was resurrected on the third day after his death, and that belief became an essential component of the religion they spread across the Roman Empire and beyond.

The new concept swiftly spread across the Jewish communities of Syria and Asia Minor.

To comprehend this incredible ending, one must first grasp the tale of Jesus of Nazareth. The Gospel stories, all of which were written long after his death, contain the most essential evidence concerning his life. The earliest, by Mark, is about 70 C.E., while the most recent, by John, is around 100 C.E. Furthermore, they are not attempts to merely describe the life of Jesus with historical authenticity.

Rather, they are declarations of faith made by sincere believers. The writers of the Gospels thought Jesus was God's son, who came into the world to rescue mankind and grant immortality to those who believed in him and followed in his footsteps.

The resurrection of Jesus, according to the Gospel writers, was compelling evidence of his divinity.