This book investigates how minorities contributed to medieval society, comparing these contributions to majority society's perceptions of the minority. In this volume the contributors define 'minority' status as based on a group's relative position in power relations, that is, a group with less power than the dominant group(s). The chapters cover both what modern historians call 'religious' and 'ethnic' minorities (including, for example, Muslims in Latin Europe, German-speakers in Central Europe, Dutch in England, Jews and Christians in Egypt), but also address contemporary medieval definitions; medieval writers distinguished between 'believers' and 'infidels', between groups speaking different languages and between those with different legal statuses. The contributors reflect on patterns of influence in terms of what majority societies borrowed from minorities, the ways in which minorities contributed to society, the mechanisms in majority society that triggered positive or negative perceptions, and the function of such perceptions in the dynamics of power. The book highlights structural and situational similarities as well as historical contingency in the shaping of minority influence and majority perceptions. The chapters in this book were originally published as special issue of the Journal of Medieval History.