Introduction

This introductory chapter provides an overview of the book's main themes. This book is about the invisible weapon of war, i.e., the prayers and liturgical rituals that were part of the battle for the faith. It tells the story of the greatest collective religious undertaking of the Middle Ages, putting front and center the ways in which Latin Christians communicated their ideas and aspirations for crusade to God through liturgy, how liturgy was deployed in crusading, and how liturgy absorbed the ideals or priorities of crusading. The hope is that, in bringing this material together as it relates to crusading, in trying to connect the evidence of liturgy and prayer found in medieval liturgical books with the larger narrative of crusading, in looking systematically and chronologically at the rites and texts that were deployed for the success of crusading and during the crusades themselves, we can understand something important about the culture of holy war in the Middle Ages.