Old and new world events at the 4th century AD

Just a showerthought really: Mormon was 15 years old when he was appointed leader of the Nephite army. This was in 325 AD, the same year as the first Nicaean Council on the other side of the Atlantic. About 6 decades later, in 382 AD, the first council that accepted the present Catholic canon was held in Rome. This was about the same time Mormon made an abridgement of the large plates of Nephi.