The music of the medieval, Renaissance, and baroque periods have been repeatedly discarded and rediscovered ever since they were new. An interest in music of the past has been characteristic of a part of the musical world since the early 19th century. The revival of Gregorian chant in the early 19th century; the "Cecilian movement" in later 19th-century Germany seeking to immortalize Palestrina's music as a sound-ideal; Mendelssohn's revival of Bach: these are some of the efforts made in the past to restore still earlier music. In recent years this interest has taken on particular meaning, representing two specific trends: first, a rediscovery of little-known underappreciated repertories, and second, an effort to recover lost performing styles, with the conviction that such music will come to life anew with the right performance. Much has been gained in the 20th century from the study and revival of instruments, playing techniques, and repertories. In this VSI, Thomas Forrest Kelly frames chapters on the forms, techniques, and repertories practices of the medieval, Renaissance, and baroque periods with discussion of why old music has been and should be revived, as well as a short history of early music revivals.