The Dungeons & Dragons Basic Set was revised in 1983 by Frank Mentzer as Dungeons & Dragons Set 1: Basic Rules. Between 1983 and 1985, this system was revised and expanded by Mentzer as a series of five boxed sets, including the Basic Rules, Expert Rules (supporting character levels 4 through 14),Companion Rules (supporting levels 15 through 25),Master Rules (supporting levels 26 through 36), and Immortal Rules (supporting Immortals – characters who had transcended levels).