In 1 Kings 11:9-13, 29-37 we have an account of the division of the kingdom of Israel.
This division was due to the fall and corruption of Solomon (vv. 9-13). In verse 11 Jehovah said to Solomon, "Because you have done this and have not kept My covenant and My statutes, which I commanded you, I will surely tear the kingdom away from you and give it to your servant."
The kingdom of God's elect was split into two: the southern kingdom, the kingdom of Judah, of one tribe (vv. 13, 36) and the northern kingdom, the kingdom of Israel, of ten tribes (v. 35). Judah was genuine, but Israel was a division in apostasy.
The reign of Rehoboam over Judah was a reign over just one tribe (v. 43b; 12:1-24; 14:21-31a).
Rehoboam, a son of Solomon, was born of an Ammonitess (14:21, 31).
Rehoboam continued the reign after Solomon (11:43b).
In 12:1-24 we see that Rehoboam suffered the division of the kingdom and lost ten tribes.