What threat did the Romans see in Christianity?
First of all, the Romans and the Jewish aristocracy killed Jesus because he was the “King” of the Jews:The “crown” of thorns was meant as mockery. Jesus was supposed to be the Son of God and the King of the Jews. That was a threat to the real Roman-backed king of Judea called Herod. The threat Rome saw in Jesus was quite real and eventually split the Jewish puppet kingdom.If Jesus hadn’t died, he could’ve proven a larger problem for the Romans. As it stands, Christianity needed some more time to build itself up and eventually start being a major factor in world history.Early Christians served God and not the emperor or the Roman pantheon.Rome wasn’t a secular state. They were heavily influenced by their own religion and worship played a large part in their way of government. The Emperor of Rome was a divine entity and the Roman Senate had multiple pagan rituals attached to its procedure.Christianity undermined that by saying Rome’s Gods and religion are wrong and corrupt. As you can imagine, that wouldn’t sit well with the Roman authorities. Christianity’s rapid spread meant that Rome’s divine rights and the sacredness of the state meant less to the followers of Christ.Christians didn’t render unto Caesar because he was divine, but because they were forced to.
What was the jewish revolt?
In fact in the Roman Empire period there were three Jewish revolts. The first began in Nero's reign, when the Jews turned a deaf ear to the impassioned pleas of their nominal king, Agrippa, not to rebel. At first the rebels enjoyed some success, when Cestius, the inept Roman commander, broke off his attack on Jerusalem for no reason and was severely harrassed during his retreat. The jews were, however, routed when they tried to follow up this success by attacking Caesaria. Eventually the legions of Titus ground down the jewish resistance. While the first revolt was essentially over when Jerusalem was recaptured and sacked in 70 CE, some fighting continued until the fall of Masada in 74 (not 73 incidentally). The second revolt occurred c 114 during Trajan's war in the East. Most of this disturbance involved the jews outside Palestine e.g. in Cyprus and Libya. But some fighting occurred in Judaea. Quietus, the Mauretania cavalry commander, quickly crushed this revolt; the diaspora was also brutally suppressed. Lastly, in 132 bar Kochba led a rebellion against Rome. His forces may have enjoyed some success. Rebel coins found in Jerusalem suggest he captured the city though scholars have doubted he did so completely if at all. It is possible that the jews destroyed legion Deoteriana. Stationed at Alexandria before the revolt, Deoteriana might have been been sent to combat it, only to be wiped out in a battle fought in the southern Judaean foothills. But the Romans soon regained the upper hand as before. Half a million jews are said to have perished, and the last rebels were captured at Bethar late in 135. Thus ended the last serious jewish quest for political independence until the 20th century.
What was the reason behind the persecution of Christians during the Roman Empire Around the 2nd century?
It is believed that the Roman people initiated the persecution of the Christians in the early Roman Empire because they were very superstitious. Roman religion was based largely on sacrifices and superstitious cult activities. They believed that participation in these activities would bring good luck and favor of the gods, but by not participating in these cult acts would adversely affect the Roman people in the way of divine intervention and punishment. Because the Christians refused to worship or sacrifice, they were persecuted by the Roman people. They believed that the Christians were the responsible for natural disasters. The Christians openly defied the Roman gods; Christians became the ultimate scapegoats.
How did Christianity first spread and become popular all over the Roman world?
Christianity did indeed spread slowly throughout the Roman world and Europe. it started, as you note, as a Middle Eastern religion. It had certainly spread to almost all of Europe by the time that printing became a method of communication. But printing enabled the rapid spread of Protestantism in its various forms. Previously the version of Christianity in western and central Europe had been solely Roman Catholicism. A religion which spread much faster was Islam. Within about 200 years of its beginning it was all across Arabia, and the Middle East, and all across North Africa, and most of Spain. Not much later it was well-established in many parts of Asia, especially south-east Asia, and in parts of sub-Saharan Africa.