Beginning of the public ministry
The date of the beginning of Christ’s ministry may be calculated from three different data found respectively in Luke 3:23; Josephus, “Bel. Jud.” I, xxi, 1; or “Ant.”, XV, ii, 1; and Luke 3:1.
The first of these passages reads: “And Jesus himself was beginning about the age of thirty years”. The phrase “was beginning” does not qualify the following expression “about the age of thirty years”, but rather indicates the commencement of the public life. As we have found that the birth of Jesus falls within the period 747-749 A.U.C., His public life must begin about 777-779 A.U.C.
Second, when, shortly before the first Pasch of His public life, Jesus had cast the buyers and sellers out of the Temple, the Jews said: “Six and forty years was this temple in building” (John 2:20). Now, according to the testimony of Josephus (loc. cit.), the building of the Temple began in the fifteenth year of Herod’s actual reign or in the eighteenth of his reign de jure, i.e. 732 A.U.C.; hence, adding the forty six years of actual building, the Pasch of Christ’s first year of public life must have fallen in 778 A.U.C.
Third, the Gospel of St. Luke (3:1) assigns the beginning of St. John the Baptist’s mission to the “fifteenth year of the Tiberius Caesar”. Augustus, the predecessor of Tiberius, died 19 August, 767 A.U.C., so that the fifteenth year of Tiberius’s independent reign is 782 A.U.C.; but then Tiberius began to be associate of Augustus in A.U.C. 764, so that the fifteenth year reckoned from this date falls in A.U.C. 778. Jesus Christ’s public life began a few months later, i.e. about A.U.C. 779.
The year of the death of Christ
According to the Evangelists, Jesus suffered under the high priest Caiphas (A.U.C. 772-90, or A.D. 18-36), during the governorship of Pontius Pilate A.U.C. 780-90). But this leaves the time rather indefinite. Tradition, the patristic testimonies for which have been collected by Patrizi (De Evangeliis), places the death of Jesus in the fifteenth (or sixteenth) year of Tiberius, in the consulship of the Gemini, forty-two years before the destruction of Jerusalem, and twelve years before the preaching of the Gospel to the Gentiles. We have already seen that the fifteenth year of Tiberius is either 778 or 782, according to its computation from the beginning of Tiberius’s associate or sole reign; the consulship of the Gemini (Fufius and Rubellius) fell in A.U.C. 782; the forty second year before the destruction of Jerusalem is A.D. 29, or A.U.C. 782, twelve years before the preaching of the Gospel to the Gentiles brings us to the same year, A.D. 29 or A.U.C. 782, since the conversion of Cornelius, which marks the opening of the Gentile missions, fell probably in A.D. 40 or 41.
The day of the death of Christ