Social: It appears that Mosiah’s attempts to “equalize” society do have some effect. He is at least able to hold his kingdom together. In fact, they are sufficiently stable that they not only do not fission, but they actually expand.
Mormon notes that they: “began to scatter abroad upon the face of the earth, yea, on the north and on the south, on the east and on the west, building large cities and villages in all quarters of the land.” This large expansion and building project appears to take place after the arrival of Alma and the creation of the churches, and before the events unfolding in future chapters. In other words, we don’t have a large time span in which this expansion takes place.
Some of the expansion clearly comes from the addition of the peoples of Alma and Limhi. While those two groups qualify for the plural nouns associated with building in verse 6, they do not seem to explain the plural in both cities and villages – not to mention all compass directions.
Somehow the kingdom of Zarahemla undergoes a population explosion in a fairly short period of time that results in large building projects. Building projects are expensive in terms of labor, and the ability to carry on multiple building projects that would contain more than one “large city” as Mormon describes them is an impressive feat. Where did all of this population and labor come from in such a short time?
The most reasonable answer is the annexation of other communities as the “land” of Zarahemla increased. Rather than waiting for a natural increase of population, there must have been large groups of people added as a unit. With the addition of these communities, probably already at least hamlets, there was sufficient population looking to the same hegemony that new city centers could be built to centralize (and unify) those populations would be important and possible.
Once again, the internal descriptions of the Book of Mormon best fit the model of many other peoples in the land who are being variously incorporated into the Nephites rather than the “Nephites/Lamanites were alone” premise.
Historical: Mormon mentions that cities and villages were built “in all quarters of the land.” Mesoamerican cultures developed a strong significance to the number four, based upon the four cardinal points. That conceptual division of the world into four quarters carried over into the establishment of other social systems that relied upon four parts:
“In an effort to keep the traditions of their fathers alive, the Nahua and Maya nations established four rulers, four governors, or four chiefs, each responsible for one quadrant of land. In Mexico we find that the four executive officers were the chiefs or representatives of the four quarters of the City of Mexico…. The entire dominion of Mexico was also divided into four equal quarters, the rule administration of which was attended to by four lords…” (“Four Quarters.” In: Reexploring the Book of Mormon. FARMS 1992, pp. 145-6).