Aaron, Lamanite King

In about AD 326, Mormon, the compiler and editor of the Book of Mormon writes about the conditions of the people:

[W]ickedness did prevail upon the face of the whole land, insomuch that the Lord did take away his beloved disciples, and the work of miracles and of healing did cease because of the iniquity of the people. And there were no gifts from the Lord, and the Holy Ghost did not come upon any, because of their wickedness and unbelief. And I, being fifteen years of age . . ."[1]

Mormon is appointed leader of the armies by the Nephites: "it came to pass that in my sixteenth year I did go forth at the head of an army of the Nephites, against the Lamanites"[2] who had come against them in force.

Now, the Lamanites had a king, and his name was Aaron; and he came against us with an army of forty and four thousand. And behold, I withstood him with forty and two thousand. And it came to pass that I beat him with my army that he fled before me.[3]

A few years later, the Nephites formed a treaty with the Lamanites and the Gadianton robbers, in which the land was divided and peace existed for ten years.

In the tenth year, Aaron sent Mormon an epistle indicating that the Lamanites were again preparing for war. Although the Nephites under Mormon's command prevail for a time, by AD 363, the Lamanites begin to conquer the Nephites in every battle.

• Book of Mormon online, "Aaron3"