This paper describes the instructional devices and innovations developed and used by Gerbert D'Aurillac (ca. 947-1003), who was elected Pope Sylvester II in 999, and their subsequent impact on education in medieval Europe. The effect of prevailing thought on Gerbert's innovations is also described. The first section examines the historical context and provides biographical information on Gerbert. Gerbert's pedagogy is described in the second section, including the planar abacus, celestial spheres, the celestial teaching machine, and the monochord. The influence of Gerbert is addressed in the third section, including the failure of his instructional devices and innovations to gain widespread use after his death. Rediscovery of his work by a subsequent pope, Alexander III, is discussed in the fourth section. Possible parallels in the 20th century are considered in the final section, including the use of mechanical teaching machines and programmed instruction in the 1950s and 1960s, as well as recent initiatives for the use of computers, the Internet, and other electronic devices. (Contains 40 references.) (MES)