Concise Bible Dictionary:
On the separation of the ten tribes, Judah and Benjamin formed a kingdom under the name of Judah. Benjamin being but a small tribe, the kingdom of Judah is sometimes spoken of as one tribe. Doubtless the territory of Simeon was also attached to Judah—that tribe being as it were lost in the land. It was not named when Moses blessed the tribes (Deut. 33, compare Gen. 49:7). Bethel, out of the portion of Benjamin, fell to the kingdom of Israel.
The temple being at Jerusalem, with the priests and Levites, Judah represented God’s people and His government upon the earth; whereas the kingdom of Israel gave itself up at once to idolatry. God, according to His promise, still caused the lamp of David to shine at Jerusalem. Many of the kings served God with purpose of heart, though others embraced idolatry. (For the succession of the kings, see KINGS.) The kingdom of Judah continued from B.C. 975 to 606 when many of the people were carried captive, though Jerusalem was not destroyed till B.C. 588.
Seventy years of captivity had been foretold by Jeremiah (Jer. 25:11-12; Jer. 29:10): these began in B.C. 606 and ended in 536 when under Cyrus the Jews returned to build the house of Jehovah; but it was not finished and dedicated until B.C. 515 (Ezra 6:15). A commission was given to Ezra in B.C. 468 (Ezra 7); and one to Nehemiah to rebuild the city in 455. It could not however be called the kingdom of Judah; only a remnant of the tribes of Judah and Benjamin returned. They were first subject to the kingdom of Persia, then to the kingdom of Greece, and after a short time of freedom under JUDAS MACCABEUS and his successors they became subject to Rome.
In B.C. 65 Syria became a Roman province and in the year 40 Herod was appointed by Rome king of Judæa, and he continued on the throne to New Testament times. The children of Israel inhabiting Judæa in those days were the descendants of Judah and Benjamin (except any individuals who may have found their way there from the ten tribes). They were the people to whom the Messiah was presented, and who refused and crucified Him. They continued their persecution in the times of the apostles, and they will be dealt with separately from the ten tribes (compare Matt. 24:4-35; Matt. 27:25).
They revolted from Rome, and in A.D. 70 Jerusalem was taken and destroyed, some of its inhabitants were sold as slaves, and thousands were slain (Dan. 9:26; Luke 21:12-24). Their descendants are scattered over the earth; but when God’s set time is come they will be brought through the fire of judgment, and a remnant will be saved, restored to their own land, and blessed under their Messiah whom they now reject (Matt. 2:6; Heb. 8:8-12).