In Luke 3:1, 2 we are given the date of the start of John’s ministry.

¹ Now in the fifteenth year of the reign of Tiberius Caesar, when Pontius Pilate was governor of Judea, and Herod was tetrarch of Galilee, and his brother Philip was tetrarch of the region of Ituraea and Trachonitis, and Lysanias was tetrarch of Abilene, ² in the high priesthood of Annas and Caiaphas, the word of God came to John, the son of Zacharias, in the wilderness.

This detailed historical data allows us to date not only the ministry of John but also the ministry of Jesus. We know from Luke 3:23 that Jesus began to minister at the age of thirty, shortly after John’s ministry began. John, being a priest, also should have begun to minister at the age of thirty, according to the law in Num. 4:3. These details also provide us with a double witness for the year of their births in 2 B.C.

Dating the ministry of John and Jesus is important in studying prophecy, because it tells us when and how Daniel’s “seventy weeks” were fulfilled at the end. Misunderstanding this, in fact, has had a very adverse effect upon the church in the twentieth century.

The Fifteenth Year of Tiberius

Tiberius was the adopted son of Augustus Caesar. Augustus himself began his career on August 19, 43 B.C. when he was first appointed consul of Rome. He died precisely 56 years later on August 19, 14 A.D. Because of this unusual coincidence, many Roman histories mention it in their writings, making it one of the most well established dates in Roman history.

Tiberius then began his reign when Augustus died, and his fifteenth year began on August 19, 28 A.D. and ended on August 19, 29 A.D. Since John was born at the time of Passover, he turned thirty and began his ministry at Passover of 29 during Tiberius’ fifteenth year. He then baptized Jesus shortly after He turned thirty in September of 29, which would have been at the beginning of Tiberius’ sixteenth year.

Those who mistakenly place Jesus’ birth in 4 B.C. argue that Tiberius’ reign started a few years earlier as a co-regent with the elderly Augustus, and so they date the start of Tiberius’ reign in 11 A.D. instead of 14 A.D. According to their theory, John’s ministry then would have started earlier in 26 A.D. By this they attempt to prove that Jesus was crucified 3½ years later at Passover of 30. However, Adam Rutherford tells us in his Bible Chronology, page 451,

“In earlier days especially, a ruler when reaching old age sometimes allowed his successor to reign jointly with him, but the historians Tacitus and Suetonius (on whom we are largely dependent for the details of Tiberius’ reign) make it very clear that Tiberius was never Joint-Emperor with Augustus, but that he was associated with Augustus only in respect of the armies and provinces and that he did not become Emperor, nor did the years of his reign begin to count, until his accession after the death of Augustus in A.D. 14. No instance is known where the years of Tiberius’ reign were reckoned from his previous partial association with Augustus.”

On page 452, Rutherford continues,

“The dating on provincial coins in actual use at the time forms first-hand indisputable evidence in those cases where such dating is equated with the years of an undisputed era. Fortunately coins of this nature belonging to the reign of Tiberius Caesar have been discovered in Syria. Some of these provincial coins were actually minted during Our Lord’s lifetime on Earth and were in everyday use throughout the Province of Syria (including Galilee, Samaria and Judaea). They would be well known to Jesus and also, of course, to St. Luke, whose words “In the fifteenth year of the reign of Tiberius Caesar” we are now discussing. These coins were actually issued from St. Luke’s own city, Antioch.

“On some of the coins the years of the reign of Tiberius Caesar are equated with the Battle of Actium, the date on which no one disputes. The Battle of Actium, which brought Augustus Caesar into supreme authority over the whole Roman world, was fought on September 2^nd, 31 B.C., and consequently, as proved by the co-ordination of the chronological data on various coins, the years of the Actian Era began with the month of September….

“One coin is double-dated, 1^st year of Tiberius and 45^th year of the Actian Era, thus revealing that the 1^st year of Tiberius synchronized with the 45^th year of Actium. As the Actian Era is universally accepted as beginning in 31 B.C., the 45^th year of that era therefore began in A.D. 14, and on the coin this year is also shown as the 1^st year of Tiberius’ reign. Similarly, on another coin the 47^th year of the Actian Era is equated with the 3^rd year of Tiberius, namely A.D. 16-17. (The beginnings of the Tiberian and Actian years only differed to the extent of seven weeks.) The provincial coins therefore definitely establish that the reckoning of the years of Tiberius’ reign counted from A.D. 14.”

It is also well known that Tiberius died on March 16, 37 A.D.

http://en.wikipedia.org/wiki/Tiberius

Josephus tells us that “Tiberius died, after he had reigned twenty-two years, and six months, and three days” (Wars of the Jews, II, ix, 5). By counting back to the start of his reign, we see that Tiberius began to reign shortly after Augustus died on August 19, 14 A.D. Josephus’ precise dating is very helpful to us in knowing what Luke meant when he said that John began to minister in the fifteenth year of Tiberius.

The Tetrarchs

Luke says that “Pilate was governor of Judea” (from 26-36 A.D.).

Luke says that “Herod was Tetrarch of Galilee.” This was Herod Antipas, son of Herod the Great, who had killed the children of Bethlehem the end of December of 2 B.C. Herod Antipas was the one who killed John the Baptist at Passover of 30 A.D. Jesus also was sent to this Herod during the time of His trial in Jerusalem three years later. He reigned until 39 A.D. when he was replaced by Herod Agrippa, who had accused Antipas of a conspiracy against the Roman Emperor Caligula.

Luke says that Herod’s “brother Philip was tetrarch of the region of Ituraea and Trachonitis.” Philip’s wife, Herodius, had divorced him about the year 27 A.D., after she fell in love with Philip’s brother, Herod Antipas. Herod then married Herodius, and two year later John the Baptist criticized this unholy union, as it violated the law of God in Lev. 18:16. Herodius hated John for this, and she later found opportunity to have John executed. Philip died in 34 A.D.

Luke says that “Lysanias was tetrarch of Abilene.” Little is known of Lysanius. Abilene was a small realm on the western slope of Mount Hermon in what is now Lebanon.

The High Priests

Luke says also that the word came to John “in the high priesthood of Annas and Caiaphas.” As I have already said, Caiaphas was the actual high priest, and Annas was his influential father-in-law (John 18:13). Annas had been the high priest earlier for ten years, but the Procurator, Gratus, had removed him from office in 15 A.D. for imposing the death penalty upon those guilty of capital crimes. Rome had reserved this right for itself, and so Gratus removed Annas from office.

Many in Judea continued to consider Annas to be the legitimate high priest, and Luke seems to agree, saying in Acts 4:6 “and Annas the high priest was there, and Caiaphas.” Caiaphas was the official high priest from 18 A.D. until his death in 37, and then Theophilus, son of Annas, replaced him from 37-41 A.D. Annas died in 40 A.D., while his son Theophilus was high priest.

These were the prominent political and religious figures forming the background of John’s ministry. Luke’s record establishes the historical setting of the ministries of John and Jesus. These facts would have been well-known to Theophilus.