The death of Riplakish and the expulsion of his descendants (verse 8) creates a situation where there is no king in the land. This condition continues for “the space of many years.” What we have is a rebellion that has removed the recognized ruling family, and replaced it with something less than a king. This condition continues for years. We may expect that during this time there is a lull in the monumental building. Certainly those who rebelled against the forced labor would not be quick to resume those labors.
When the king returns, it is Morianton. We hear that he is a descendant of Riplakish. There is a break in the lineage here, and we do not know the nature of the break. Knowing that Morianton is a “descendant of Riplakish” tells us that he at least lays claim to a continuation of the Jaredite king-line, and indeed Morianton becomes one of the king-lineage. It is significant that the return of the king is the result of war. Reading between the lines, there was a complete break with the previous lines, and Morianton returns with an army to conquer the land and reestablish himself.
Morianton’s name shows up in the Nephite record with both a namesake and a land of Morianton (Alma 50:25-29). It is unclear if the land of Morianton already had that name, or if it was named for the contemporary Morianton who was ruler in that land. The land of Morianton is on the northern border of the land of Zarahemla, and therefore in direct proximity to the Jaredite homelands. The name is certainly retained culturally, even if the land of Morianton was not named for this particular Jaredite king.