The Son of God came among men during the beginning of the Roman Peace which began with Augustus in 6 AD and ended with the death of Marcus Aurelius in 180 AD. This was a time of relative peace brought about by the Roman Juridical System and maintained by the Roman Legions who even during this time were occasionally putting down revolts along the border of the Roman Empire. Further, there was not true peace in the Roman heart because they sought after "Blood Sport" in the Coliseum of Rome where criminals were put to death, where gladiatorial combats took place, where men and women were devoured by wild beasts. In 80 AD, during 100 of ceremonies 5,000 wild animals were put to death. This is also where many Christians were martyred during the Roman persecutions.
We find at Christ birth the angels singing "Glory to God in the highest and on earth peace to those on whom his favor rests." (Lk 2:14) So, you may rightfully ask, "What kind of peace did Christ come to bring on earth?" First of all, it is a peace of reconciliation of mankind with God which he brought about by the terrible price of his blood. It is not a peace brought about by armed conflict because God's peaceful kingdom could only come about by a change of heart by the power of the Spirit. It is written in the Bhagavad Gita, "When a man surrenders all his desires that come to the heart and by the grace of God finds the joy of God, then his soul has indeed found peace." (Gita, I:55) The sinful desires of the human heart are many but fall into seven categories: Pride, Avarice, Envy, Lust, Anger, Gluttony and Sloth. These are the root tendencies of the our fallen nature which bring a conflict in the soul between what we desire and what should desire. The commandments of God direct us to restore order but the power by which we can do this is God's strength that comes by the Holy Spirit. And when we sin Christ reconciles us with God as he said to the apostles on the day of his Resurrection, "Peace be with you; as the Father has sent me, so I send you." And when he had said this, he breathed on them and said to them, "Receive the Holy Spirit. Whose sins you forgive are forgiven them, and whose sins are retained are retained." (Jn 19:21-23) There is much conflict in the world today because men choose to follow their own desires instead of following Christ.