During the lives of Jacob and then his son Enos after him, the Nephites tried to teach the Lamanites the gospel, but it was futile, for they would not listen. They were led by their evil nature and became wild, ferocious, bloodthirsty people, full of idolatry and filthiness. They lived in tents, shaved their heads, and wore only loincloths. Many of them ate nothing but raw meat.
By the time of Enos's son Jarom, around 350 BC, the Nephites had become strong in the land with fortified cities that protected them from the Lamanites. But the Lamanites were far, far more numerous than the Nephites. The Lamanites loved murder and would drink the blood of beasts.
As the Nephites spread out over the land, growing greatly in number, they became extremely rich in gold, silver, and precious things. They had fine workmanship of wood, iron, copper, brass, and steel, making buildings and all kinds of tools to till the soil; and all kinds of weapons of war, including bows and arrows, darts, javelins, and all other preparations for war.
Over the next hundred years, the more wicked part of the Nephites were destroyed. Jesus severely punished them to verify what he had told their ancestors about what would happen if the people did not keep his commandments. But the righteous Nephites he kept safe from their enemies.
Around 250 BC, a man named Mosiah was king of the Nephites. He was warned by Jesus to flee from the land of Nephi into the wilderness with as many people as would heed Jesus's warning. They were led by many prophets and were protected in the wilderness by the power of God until they eventually came to the land of Zarahemla where the Mulekites lived.
There was great rejoicing among the Mulekites at the arrival of the Nephites when they realized Jesus had sent with them the records of the Jews. For the Mulekites were the descendants of Mulek, whose people Jesus lead out of Jerusalem and brought to America in the 500s BC. They settled in the land south of where the Jaredite civilization came to an end. But the Mulekites had not brought with them any records of their people.
Although the Mulekites had become a numerous people, without any records of their ancestors, their language had become so corrupted that the Nephites could not understand them, so King Mosiah saw to it that they were taught the language of the Nephites, and the Mulekites united themselves with the newcomers and became Nephites with Mosiah as their king.
During King Mosiah's reign, he was brought a large stone with engravings on it, and by the power of God, Mosiah was able to translate it. It was the record of the Jaredites, who were led to America at the time of the Tower of Babel and established a civilization of millions of people before being utterly destroyed by Jesus's righteous punishments, leaving behind only scattered bones in the land to the north.
Now at this time there were many of King Mosiah's people who wished to once again possess the land of Nephi, where the Nephites had lived before coming to Zarahemla. A first expedition was sent, but nearly all of them were killed in the wilderness before returning to Zarahemla. A second expedition headed by a man named Zeniff then headed off into the wilderness, but did not report back.