Coriantumr, a descendant of Zarahemla, dissented from the Nephites and led a Lamanite army against them. He was a large and mighty man (Helaman 1:15). The Lamanite king Tubaloth, son of Ammoron, appointed him to command the army, judging that his strength and wisdom could prevail over the Nephites (Helaman 1:16).
Because of contention in the Nephite government, the land of Zarahemla was left without sufficient guards, and Coriantumr marched on the city so quickly that the Nephites had no time to assemble. He cut down the watch at the city’s entrance, took the whole city, and struck the chief judge Pacumeni against the wall so that he died (Helaman 1:20-21). He then pressed north toward the city of Bountiful, intending to cut his way through to the north parts of the land (Helaman 1:23).
His march through the center of the land gave the Nephite general Moronihah the advantage. Moronihah sent Lehi to head off the Lamanites before they reached Bountiful, and Lehi drove them back toward Zarahemla. Moronihah met them in their retreat in a bloody battle; the Lamanites were surrounded on every side, and Coriantumr was slain. His bold march had plunged the Lamanites into the midst of the Nephites, leaving the entire army in Nephite power and forced to yield themselves into Nephite hands (Helaman 1:30, 32).