By now, the mention of wars is no surprise. It is, however, important to remember that “Lamanite” is a political, not a genealogical, definition. “Lamanite” is a collective term for anyone who opposes the Nephites (Jacob 1:14).
Almost certainly, these particular Lamanites are not those who had been vexing the city of Nephi. Those Lamanites would have had to come 180 miles from their own region to find Zarahemla. It is much more likely that these opponents are is close proximity to the land of Zarahemla, perhaps continuing hostilities that had begun years before the arrival of the Nephites. (See commentary accompanying Omni 1:17.)
Master’s candidate Donald Arthur Cazier suggests that “the reign of Mosiah I seems to have been singularly free from wars and contentions, but more than once Benjamin, during his reign, was forced to defend his people against a Lamanite invasion.” In addition to the Lamanite invasions, which had no discernible connection to the change of power from Mosiah1 to Benjamin, the eruption of the internal religious contentions during Benjamin’s reign (W of M 1:14–16) suggests that it was this very change in rulership that offered the opportunity for the rise of the contentions. Mosiah1 would have had a honeymoon period where the importance of the new union quelled possible dissent. The death of a king is often a dangerous time in monarchies, and in Zarahemla, coming so freshly from a tradition completely different from that of the Nephites, it is likely that the internal convulsions were ignited by the possibilities offered by the transition from one king to another.