The execution of Amalickiah took place on the last day of the year that both the Nephites and the Lamanites were using at this time. When they Lamanites awake on the “first morning of the first month” they find their leader dead. This would have been disturbing on any day, but to happen on the first day of the new year would be a particularly dangerous omen:
“Amalickiah had almost gained victory over the Nephites on the east seashore when Teancum, a Nephite captain, stole at night into Amalickiah’s camp “and put a javelin to his heart,” then slipped away without awakening anybody. This was the last night of their year. (In that area war would be likely to occur between October and February, when rains and floods did not block movement; since Amalickiah was already well into his campaign at this time, it seems likely that this year end/beginning was at or near the winter solstice.) “And now, it came to pass in the twenty and sixth year of the reign of the judges over the people of Nephi, behold, when the Lamanites awoke on the first morning of the first month [of the year], behold, they found Amalickiah was dead in his own tent… . And now, when the Lamanites saw this they were affrighted; and they abandoned their design, … and retreated with all their army into the city of Mulek, and sought protection in their fortifications” (Alma 52:1-2).
Throughout later Mesoamerican societies immense effort was expended to determine whether a period of time was lucky or unlucky for some endeavor. Omens were regularly sought and frequently were tied to events of the last, or first, day. It would be highly characteristic of Mesoamericans to act as the Lamanites did upon the death of Amalickiah. To awaken on the first day of a new year to find their leader dead would have been far more unnerving to their omen-conscious feelings than we moderns may appreciate.” (John L. Sorenson, An Ancient American Setting for the Book of Mormon [Salt Lake City and Provo: Deseret Book Co., Foundation for Ancient Research and Mormon Studies, 1985], 275.)
Chronological: The twenty-sixth year of the reign of the judges correlates to approximately 68 B.C.