Takeshi Inomata from the University of Arizona is one of the top dirt archaeologists currently working in Mesoamerica. He specializes in the sites of Aguateca and Ceibal in the Petexbatun region of Guatemala.  He just published a major article in the Proceedings of the National Academy of Sciences, PNAS, entitled "High-precision radiocarbon dating of political collapse and dynastic origins at the Maya site of Ceibal, Guatemala."

One date stands out. When Inomata finally got enough radiocarbon dates from a single site to determine events with temporal precision, he found that ca. 75 BC was the time when fortifications first appeared at Ceibal in response to intensified warfare. One archaeologist remarked that it seemed that some militaty genius had taught and supervised a new defensive warfarre actic. What was going on in the Nephite world ca. 75 BC?  Captain Moroni became commander of Nephite forces, he fortified every city in the land with new tactics such as digging trenches lined with wooden spears.