John answered them all, "I indeed baptize you with water, but he comes who is mightier than I, the latchet of whose sandals I am not worthy to loosen. He will baptize you in the Holy Spirit and fire,

 (i) Tiberius was the successor of Augustus and therefore the second of the Roman emperors. As early as A.D. 11 or 12 Augustus had made him his colleague in the imperial power but he did not become sole emperor until A.D. 14. The fifteenth year of his reign would therefore be A.D. 28-29. Luke begins by setting the emergence of John against a world background, the background of the Roman Empire. 