We often hear that our world 'is more multilingual than ever before', but is it true? This book shatters that cliche. It is the first volume to shine light on the millennia-long history of multilingualism as a social, institutional and demographic phenomenon. Its fifteen chapters, written in clear, accessible language by prominent historians, classicists, and sociolinguists, span the period from the third century BC to the present day, and range from ancient Rome and Egypt to medieval London and Jerusalem, from Russian, Ottoman and Austro-Hungarian empires to modern Norway, Ukraine, and Spain. Going against the grain of traditional language histories, these thought-provoking case studies challenge stereotypical beliefs, foreground historic normativity of institutional multilingualism and language mixing, examine the transformation of polyglot societies into monolingual ones, and bring out the cognitive and affective dissonance in present-day orientations to multilingualism, where 'celebrations of linguistic diversity' coexist uneasily with creation of 'language police'.