The unit's early years had many evolutions, the first of which was as a service of the Indiana University Extension Division, which was created in 1891. In 1913, it was formally organized and began expanding following a shift in emphasis from formal course instructional technology to noncredit services and activities. After WWI, the Wilson administration gifted war materials to the Extension Division and the service responsible for circulating lantern slides, loaning exhibits, and collecting educational films became known as the Bureau of Visual Instruction. During the 1920s, the Bureau expanded its reach to begin lending materials outside of Indiana and in 1931 began renting 16mm film in addition to other visual aids. Under the direction of L.C. Larson, the unit was renamed the Bureau of Audio-Visual Aids during WWII and became one of the largest of such services, most of which were based in major universities. This growth corresponds with the surge in demand and ubiquity of audio-visual materials being used for educational purposes during the war and in the postwar period. Between 1939 and 1945, the number of sound film prints offered by the Indiana University Audio-Visual Center (as it was called from 1945 to the early 1990's) increased by nearly 1000 percent. Indiana University provided leadership in best practices for audio-visual distribution units and in 1940 received a grant from Coronet, an educational film production company, to contribute to and analyze the curriculum content of their films. In addition to collaborations with producers, the AVC produced hundreds of films over the next several decades through cooperation with graduate students and faculty in the Department of Instructional Systems Technology in the School of Education. In the late 1970's, the Audio-Visual Center, along with many similar organizations, started purchasing and renting videocassettes instead of the much more expensive 16mm films. However, the film collection continued to circulate, and most of the films were not discarded with the changeover in format. The ease of duplicating videos (legally or illegally) spelled the demise of the pooled resource model, and many university-based rental centers closed during the 1990's. In 2006, Indiana University decided to close its rental service (now under the auspices of Instructional Support Services), and the collection of about 50,000 reels of 16mm film and 7,000 videos came under the aegis of the IU Library System. The Audio-Visual Center was the exclusive distributor of films produced by NET (National Educational Television, the predecessor to PBS). About 1,000 films were produced by the AVC's own staff, with consultation by IU faculty, including exemplary series on anatomy, microbiology, and the arts.