The James Madison class of submarine was an evolutionary development from the Lafayette class of fleet ballistic missile submarine. They were identical to the Lafayettes except for being designed to carry the Polaris A-3 missile instead of the earlier A-2. During the late 1970s and early 1980s, select units were further modified to carry Trident-I (C-4) missiles. This class, together with the George Washington, Ethan Allen, Lafayette, and Benjamin Franklin classes, comprised the "41 for Freedom."