Charlemagne (768–814) was arguably the greatest king in European history. Indeed, it can be said that Charlemagne invented the idea of Europe. As Morrissey, professor of French literature at the University of Chicago, makes clear, the first holy Roman emperor has historically meant different things to different eras—there's "a Charlemagne for every taste"—and the author provides an exhaustively researched account of these various representations and meanings. Charlemagne has always been viewed through a combination of history, myth and poetry (especially the famous epic, The Song of Roland), Morrissey says, yielding so plastic an image that Charlemagne has been used to defend both sides of an argument, as during Revolutionary debates over the clergy. In Part One, Morrissey describes how Charlemagne was "imagined" from the time of his death to the 16th century as "[w]arrior, protector of Christendom, guarantor of justice, defender of the poor, legislator" and "adept statesman." While early historical accounts celebrated Charlemagne as a Christian conqueror, later accounts glorified him as a limited monarch who freely shared power with his people; this image of an anti-absolutist Charlemagne, however, was problematic for the Bourbon monarchs of the 17th and 18th centuries. In the late 19th century, Charlemagne, now viewed as a German, became increasingly irrelevant to French history. Today, with the idea of a unified Europe ascendant, Charlemagne has never been more relevant, claims Morrissey. The author combines history and literature in a provocative study that sheds as much light on the eras he covers as on Charlemagne himself. Illus. not seen by PW.(Mar.)