Twelve Tribes of Israel
The Twelve tribes of Israel were the sons of Jacob (renamed Israel) and were the lineage of the Jewish people. It was the cultural custom to not only identify as being Hebrews, but also which particular 'house' one came from.
This information of tribe lineage was lost sometime after the diaspora. But the book of Revelation implies that God remembers which "house" every Jew alive descends from, and will make 144,000 specific appointments from these tribes in the Last Days. (Revelation 7:1-7 )
Each tribe was given a section of the promised land for themselves and their descendants. Levi, the priestly branch, was not given an inheritance, but was given grazing rights in the suburbs of forty-eight cities scattered throughout Israel. Instead the land divisions were kept at twelve by dividing the lineage of Joseph by his two sons: Ephraim and Manasseh. (In the days of the Kingdom of Judah, all the Levites defected from the rival Kingdom of Israel and have remained associated with Jewry to this day.)