Israel was the northern of the two kingdoms formed when the Israelite monarchy divided after Solomon’s reign. Ten tribes met Solomon’s son Rehoboam at Shechem, rejected his refusal to lighten their burdens, and made Jeroboam king in his place, leaving only Judah following the house of David around 931 B.C. (1 Kings 12:1-20). Because the tribe of Ephraim led these tribes, the Book of Mormon’s Isaiah passages call the northern kingdom Ephraim as well as Israel. Ephraim and Manasseh together are named against Judah (2 Nephi 19:21).
Samaria was its capital and the seat of its kings; Isaiah names Samaria as the head of Ephraim and pairs Ephraim with the inhabitants of Samaria. After Ephraim departed from Judah, Isaiah warned that the Lord would bring the king of Assyria upon the land, and declared that the Lord’s word sent to Jacob had lighted upon Israel (2 Nephi 17:17, 19:8-9).
In the days of Ahaz, king of Judah, the northern kingdom joined Rezin of Syria in a confederacy to attack Jerusalem and set their own king over Judah. Isaiah foretold that the plan would not stand and that within sixty-five years Ephraim would be broken so that it was no longer a people; he linked this to the king of Assyria, who carried much of the northern population into captivity (2 Nephi 17:8, 21:13). The same prophecies place the scattering of Israel before a later gathering, when the envy of Ephraim would depart and Ephraim and Judah would no longer vex each other (2 Nephi 21:13).