Christ united the Roman, Greek, Chaldean and Egyptian through the power of the Word of God

… through the supreme efficacy and power of the Word of God He [Christ] united most of the nations of the East and the West. This was accomplished at a time when these nations were opposed to each other in hostility and strife. He led them beneath the overshadowing tent of the oneness of humanity. He educated them until they became united and agreed, and through His spirit of conciliation the Roman, Greek, Chaldean and Egyptian were blended in a composite civilization. This wonderful power and extraordinary efficacy of the Word prove conclusively the validity of Christ. Consider how His heavenly sovereignty is still permanent and lasting. Verily, this is conclusive proof and manifest evidence. (Abdu'l-Baha, The Promulgation of Universal Peace, p. 367)