Obviously a title connoting the political and military leadership of the Jewish people.

OT: From the 18th to 11th centuries, the Hebrews were a loose confederation of "tribes," not a
monarchy. God was considered their king. The first human "kings" were Saul, David, and
Solomon. Thereafter the "Kings of Israel" and the "Kings of Judah" ruled over separate realms.
After the Babylonian exile, "Judah" was usually called "Judea," the land of the "Jews." The
exact title "King of the Jews" is not used in the OT, but obviously there were many "kings" over
the people.

NT: The phrase "King of the Jews" is only applied to Jesus, once at his birth (Matt 2:2) and 17
times at his trial and crucifixion (in all 4 Gospels, but only by his opponents). Jesus is also
called "King of Israel" four times. Jesus himself refuses to be made king (Matt 4:8-10; John
6:15), but often speaks of the "Kingdom of God" and uses kings as characters in his parables.