From 1 Nephi through Omni the prophets kept the small plates and the king kept the large plates (see Jarom 1:14). A major shift happened at this point. Amaleki gave the small plates to King Benjamin; the small plates were full at this point (see Omni 1:30). From King Benjamin’s time forward, the religious and the historical information were kept on the large plates. The small plates were not added until after 130 B.C. Mosiah through 4 Nephi is Mormon’s abridgement of the large plates.