The foundation of Moroni's system of fortification was earthworks encircling the place to be defended. The earth was dug from the outside, by which means a ditch was formed. Sometimes walls of stone were erected. On the top of the earthworks strong defenses of wood, sometimes breastworks, in some cases to the full height of a man, were raised; and above these a stockade of strong pickets was built, to arrest the flight of the stones and arrows of the attacking forces. Those arrows, etc., that passed above the pickets fell, without doing injury, behind the troops who were defending the wall. Besides these walls, towers were raised at various convenient points, from which observations of the movements of the enemy were taken, and wherein corps of archers and slingers stationed during the actual continuance of the battle. From their elevated and commanding position these bodies of soldiers could do great injury to the attacking force.
To make this subject yet plainer we insert a few extracts, from the Book of Mormon, that have a bearing thereon.
In the year B. C. 73 a severe war was being waged, in which Moroni had command of the Nephite armies and Amalickiah of those of the Lamanites. It is written that at this time Moroni erected small forts, or places of resort; throwing up banks of earth round about, to enclose his armies, and also building walls of stone to encircle them about, round about their cities and the borders of their lands; yea, all round about the land; and in their weakest fortifications he did place the greater number of men; and thus he did fortify and strengthen the land which was possessed by the Nephites.
The year following Moroni caused his soldiers to dig up heaps of earth round about all the cities, throughout all the land which was possessed by the Nephites; and upon the top of these ridges of earth he caused that there should be timbers; yea, works of timbers built up to the height of a man, round about the cities. And he caused that upon these works of timbers there should be a frame of pickets built upon the timbers round about; and they were strong and high; and he caused towers to be erected that overlooked those works of pickets, and he caused places of security to be built upon those towers, that the stones and the arrows of the Lamanites could not hurt them. And they were prepared, that they could cast stones from the top thereof, according to their pleasure and their strength, and slay him who should attempt to approach near the walls of the city. Thus Moroni did prepare strongholds against the coming of their enemies, round about every city in all the land.