Jesus asked his heavenly Father to make his followers completely one "so that the world may know that you have sent me." (John 17:20-23). The Father granted his Son's prayer. The history of the Church records how Christians, in unity, have recounted the Lord's teachings, passion, and resurrection, celebrated the holy sacraments instituted by Christ, and made disciples of all peoples. In fact, the unity of the Church offers a compelling witness to the truth of the gospel. Reflecting on the amazing survival and expansion of the early Church, Saint Augustine of Hippo (354-430 AD), wrote: "I should not believe the gospel except as moved by the authority of the Catholic Church." Bearing witness to God's powerful work among his people, Bishop Richard Gilmour presents Church History to 1500 for Young Readers - volume one in a two-part series. "Remember the days of old, consider the years long past; ask your father, and he will inform you; your elders, and they will tell you." (Deut 32:7)