Luke 3:2

Annas and Caiaphas were high priests. The Jews accepted only one high priest, who held that position for life. But Pilate, the Roman governor, had set aside Annas, and appointed Caiaphas, son-in-law of Annas, as high priest in his place. Both were called high priests at the same time. The word of God came to John. This is God's call for John to begin his work. John is 30 years old at this point, 6 months older than Jesus.