Radak: All of these - Bnei Gad, Bnei Reuven and Chetzi Menasheh recorded their lineage for the war against the Hagri'im. They were counted according to their fathers' families when they went out to war.

Radak #1: Yes. This refers to Yarav'am ben Yo'ash of Yehudah ¹ , Melech Yisrael. Yosam's father Uziyah became king in Yarav'am's 27th year, and he reigned 52 years. Yarav'am reigned only another 14 years. How could Yosam reign together with Yarav'am? After Uziyah became a Metzora, Yosam acted as king.

Radak #2: No. In the time of each ² , they recorded lineages for war. Malbim - when Yo'ash Melech Yisrael conquered Amatzyah Melech Yehudah, Melech Yehudah was humbled to Melech Yisrael, until Uziyah overpowered two years before he became a Metzora. Until then, the kingship was called on Yarav'am's name. This is why it says that Hoshe'a and Amos prophesized in the days of Yarav'am. Here discusses when also Yehudah was under Yarav'am. He returned Yisrael's border from Levo Chamas until Nachal ha'Aravah. Until then, Aram ruled over Yisrael, and they spread onto the inheritance of Bnei Gad and Bnei Reuven. Yarav'am made war, and returned them. Soldiers recorded their lineage; this was until the days of Yosam. In his days, Tiglas Pil'eser exiled them, and their lineage ceased.