“At that time,
Herod the tetrarch
Ἐν ἐκείνῳ τῷ καιρῷ ἤκουσεν Ἡρῴδης ὁ τετραάρχης τὴν ἀκοὴν Ἰησοῦ,
This mention of Herod can be found in all 3 synoptic gospels, Mark, chapter 6:14, and Luke, chapter 9:7, and here. The Roman educated Herod, was the ruler or tetrarch of Galilee and Perea from 4 BCE-39 CE, as a client part of the Roman Empire. This Herod Antipas was the son of Herod the Great. He built the capital city of Galilee Tiberias, as he was a favorite of the Roman Emperor Tiberius (14-37 CE.). Mathew has his traditional transition phrase, “At that time (Ἐν ἐκείνῳ τῷ καιρῷ).” Herod the tetrarch heard reports, news or rumors about Jesus (ἤκουσεν Ἡρῴδης ὁ τετραάρχης τὴν ἀκοὴν Ἰησοῦ). Thus, we have the intersection of the Galilean official of the Roman Empire, Herod, and Jesus.