Let's lookout at what happened to the twelve tribes descended from the twelve sons of Jacob. After they came out of Egypt in 1200 B.C. they became thirteen tribes through the two sons of Joseph, Ephraim and Manasseh each having been given a portion. But then, with Joshua having given the Levites cities in each of the tribal lands, the number of portions went back to twelve.
In 722 the Assyrians conquered the ten northernmost tribes. leaving only the trirbal lands of Benjamin and Judah. They were joined by the priestly cities scattered through them.
In 597 B.C. Babylon, our modern Iraq, led those tribes and cities off to Babylon. where they remained until 535 B.C. when Persia, our modern day Iran, released them. The Bible regarded the Persian king, Cyrus to be their Savior.
With the tribe of Benjamin joining up wth that of Juda, the resulting land became known simply as Judah.