Luke 3:1

Now in the fifteenth year of the reign of Tiberius Caesar,
&c.] Emperor of Rome, and the third of the Caesars; Julius was the first, and Augustus the second, in whose time Christ was born, and this Tiberius the third; he was the son of Livia, the wife of Augustus, but not by him; but was adopted by him, into the empire: his name was Claudius Tiberius Nero, and for his intemperance was called, Caldius Biberius Mero; the whole of his reign was upwards of twenty two years, for he died in the twenty third year of his reign {g}; and in the fifteenth of it, John began to preach, Christ was baptized, and began to preach also; so that this year may be truly called, "the acceptable year of the Lord".

Pontius Pilate being governor of Judea;
under the Emperor Tiberius, in whose reign the Jewish chronologer ^F8 places him, and the historian

and Herod being tetrarch of Galilee;
this was Herod Antipas, the son of Herod the great, and brother of Archelaus; the above chronologer ^F11 calls him also a tetrarch, and places him under Tiberius Caesar: he is sometimes called a king, and so he is by the Ethiopic version here called "king of Galilee"; and in the Arabic version, "prince over the fourth part of Galilee"; besides Galilee, he had also Peraea, or the country beyond Jordan, as Josephus ^F12 says, and which seems here to be included in Galilee; (See Gill on Matthew 14:1).

And his brother Philip tetrarch of Iturea, and of the region of
Trachonitis:
Pliny ^F13 makes mention of the nation of the Itureans, as belonging to Coele Syria; perhaps Iturea is the same with Batanea, or Auranitis, or both; since these with Trachon, the same with Trachonitis here, are allotted to Philip by Josephus ^F14: it seems to take its name from Jetur, one of the sons of Ishmael, ( Genesis 25:15 ) Trachonitis is mentioned by Pliny ^F15, as near to Decapolis, and as a region and tetrarchy, as here: Ptolemy ^F16 speaks of the Trachonite Arabians, on the east of Batanea, or Bashan: the region of Trachona, or Trachonitis, with the Targumists ^F17, answers to the country of Argob. This Philip, who as before by Josephus, so by Egesippus ^F18, is said, in agreement with Luke, to be tetrarch of Trachonitis, was brother to Herod Antipas, by the father's, but not by the mother's side. Philip was born of Cleopatra, of Jerusalem, and Herod of Malthace, a Samaritan {s}: he died in the twentieth year of Tiberius ^F20, five years after this:

and Lysanias the tetrarch of Abilene:
mention is made of Abila by Pliny ^F21, as in Coele Syria, from whence this tetrarchy might have its name; and by Ptolemy ^F23, it is called Abila of Lysanius, from this, or some other governor of it, of that name; and the phrase, "from Abilene to Jerusalem", is to be met with in the Talmud ^F24, which doubtless designs this same place: who this Lysanias was, is not certain; he was not the son of Herod the great, as Eusebius suggests ^F25, nor that Lysanias, the son of Ptolemy Minnaeus, whom Josephus ^F26 speaks of, though very probably he might be a descendant of his: however, when Tiberius Caesar reigned at Rome, and Pontius Pilate governed in Judea, and Herod Antipas in Galilee, and Philip his brother in Iturea and Trachonitis, and Lysanias in Abilene, John the Baptist began to preach and baptize; to fix the area of whose ministry and baptism, all this is said.

F7 Suetou. Octav. Aug. c. 62, 63. & Tiberius Nero, c. 21, 49, 73.
F8 R. David Ganz par. 2. fol. 15. 1.
F9 Joseph. de Bello, Jud. l. 2. c. 9. sect. 2, 3.
F11 Par. 1. fol. 25. 2.
F12 De Bello Jud. l. 2. c. 6. sect. 5.
F13 Nat. Hist. l. 5. c. 23.
F14 Ib. ut supra. (de Bello, Jud. l. 2. c. 9. sect. 2, 3.)
F15 Nat. Hist. l. 5. c. 12.
F16 Lib. 5. c. 15.
F17 Targum Jon. in Deut. iii. 4. 14. 1 Kings iv. 13. & T. Hiefos. in Deut. iii. 14. & Numb. xxxiv. 15.
F18 De Excid. l. 1. c. 46. & 3. 26.
F19 Joseph de Bello Jud. l. 1. c. 28.
F20 Ib. Antiqu. l. 18. c. 6.
F21 Lib. 5. c. 18.
F23 Lib. 5. c. 15.
F24 T. Bab. Bava Kama, fol. 59. 2.
F25 Hist. Eccl l. 1. c. 9. 10.
F26 De Belle Jud. l. 1. c. 13. sect. 1.