Here’s the history: we read in Mosiah 9:1–7 of Zeniff, who was King Noah’s father. This is about 200 BC.
Zeniff took two trips from Zarahemla to Nephi. The first ended in failure because of infighting. During the second trip, Zeniff took “as many as were desirous to go up to possess the land” and headed back to Nephi. This time, they were “smitten with famine and sore afflictions.” Nevertheless, a few of them arrived at Nephi and convinced the king of the Lamanites to “depart out of the land.”
So, this group of Mulekite-Nephites possesses the land, repairing the walls of the city of Nephi (also called Lehi-Nephi) and the city of Shilom. My question is: how many people came with Zeniff, and how did they grow into a kingdom by the time of King Noah?
There are several journeys mentioned between Zarahemla and Nephi. The biggest may have been the first failed one, which ended with only 50 survivors after the infighting. Zeniff led another group, which is described as a “considerable number” in Omni 1:29. The other trips were smaller, 16 strong men (Mosiah 7:2) and 43 people sent from Nephi to Zarahemla (Mosiah 8:7).
So, the question is, how many were the “considerable number,” and did it include a lot of women and children? This is a key question that is not answered in the text, but given that the first trip ended badly, perhaps a reasonable answer to the second question is “no.” Or perhaps Zeniff’s trip was more successful precisely because there were women and children there? Zeniff wanted to treat the Lamanites kindly, unlike the first unnamed leader, who is described as “stiffnecked man” who “caused a contention among them” over the issue of destroying the Lamanites.
We must also consider the fact that during Zeniff’s trip there was “famine and sore afflictions,” so perhaps some people died during this trip?
In any case, let’s name a large number of people for Zeniff’s trip, perhaps 150, which would have been very large compared to the other trips that were taken.
About 40 years later, we read about King Noah and his rather large kingdom filled with gold, silver, ziff, copper, brass and iron. Noah laid a tax of 20 percent on everybody to build huge buildings and ornamented the buildings with “fine work of wood, and all manner of precious things.” (Mosiah 11:8).
The taxes were high enough that Noah and a coterie of priests were all maintained in luxury and laziness.
This kingdom must have grown immensely. If we assume, say 40 women of child-bearing age in the original group with five children each (which, given the primitive conditions, may be too many — remember infant mortality was very high in those days), we do not get to a kingdom large enough to maintain King Noah in the luxury to which he became accustomed. In addition, we must ask where did Noah and his large court get all the “wives and concubines?” (Mosiah 11:4).
Let’s do the math. 40 women with five children each equals 200 extra people after 15 years. The next generation would be have women (100 girls). Each of them have five children, adding an additional 500 people. But keep in mind people are also growing old and dying. No matter how you slice it, the Mulekite-Nephite population could not have been greater than 1,500 people at the most, and probably a lot less. A large percentage of this population would have been under 10.
I believe that the Book of Mormon is a real history involving real people. So, the point I am getting at is that we cannot limit ourselves when thinking of the different groups of people and how they integrated with the people around them.
A much more likely scenario, in my opinion, is that other people began to move to the land of Nephi when they saw the industrious Mulekite-Nephites rebuild the city. Obviously the Lamanites had let the place fall to pieces. People are attracted to growth, and the new people brought industry and growth and perhaps even jobs. This would explain all of the mining and timber and farming and building going on. From an economic standpoint, the land of Nephi became an engine of growth for the entire region. Many of the Lamanites or even other groups of people moved there and helped the region grow.
I would postulate that the same thing happened with Nephi moved away from the Lamanites and originally settled the land of Nephi (described in 2 Nephi 5:5–8). He moved there with a few dozen people, yet very quickly he was being named a king and building a temple. I believe that Nephi attracted a lot of newcomers and that the Nephites of his day included people from Jerusalem as well as many people who were already in the Americas. This would also explain why it is so difficult to find Middle Eastern DNA in the Americas — there was a lot of mixing with existing populations.
So, to sum up, King Noah’s kingdom probably involved a lot of unexpected people. There were probably Lamanites and even many non-Israelites. The Book of Mormon lands were probably much more of a melting pot than we like to think.