2 Chronicles 22:1

And the inhabitants of Jerusalem made Ahaziah his youngest son king in his stead,.... He being the only surviving one of the sons of Jehoram, the same with Jehoahaz, 2 Chronicles 21:17 who was saved when the rest were taken captive and slain, by his mother Athaliah, and he made his escape, and that she also escaped is clear from

2 Chronicles 22:10

for the band of men that came with the Arabians to the camp; that is, of the Philistines, 2 Chronicles 21:16, which band seems to be a band or company of thieves and robbers, as the Septuagint, cruel and barbarous, as the action ascribed to them shows:

[for they] had slain all the eldest; sons of Jehoram; the Philistines and Arabians only carried them away captives, but those slew them in cold blood:

so Ahaziah the son of Jehoram king of Judah reigned; being declared his successor by the inhabitants of Jerusalem.