Luke 3:1
Now in the fifteenth year of the reign of Tiberius Cæsar, Pontius Pilate being governor of Judæa, and Herod being tetrarch of Galilee, and his brother Philip tetrarch of Ituraea and of the region of Trachonitis, and Lysanias the tetrarch of Abilene,
The fifteenth year of the reign of Tiberius Caesar marks the dating of the beginning of the ministry of John the Baptist. At that same time the surrounding territories are identified by the rulers governing them. This opens the record of John the Baptist as the forerunner of Christ, who goes before the face of the Lord to prepare His ways.