The excavations at Cluny resulted from a project of 1926, sponsored by the John Simon Guggenheim Foundation, to make a series of cavalier restoration drawings of three great French monastic sites—Cluny, St. Martin at Tours, and St. Martial at Limoges. The great buildings at these sites needed to be restored to ‘visual history’ in order to give increased clarity to our understanding of medieval architecture. A cavalier study can never be more than a beginning, however; the finished study of a ruined site necessarily calls into play the refined techniques which classicists have developed in their work. A medieval monastic site may turn out to be as broad as Knossos, demanding a lifetime of investigation, because of the extent, the long history, and the varied influences represented in the architectural remains. This proved to be the case at Cluny, where the architectural remains span eleven centuries.