In the tumultuous landscape of medieval Iberia, where Christian kingdoms struggled against Muslim polities for control of a contested peninsula, a powerful ideological transformation was underway—one that reshaped the course of history and the very nature of holy war. This groundbreaking book unveils how the sacred kingship and political theology forged under Charlemagne's Carolingian Empire laid the foundational framework for the Iberian Reconquest, long before the call of the First Crusade echoed across Europe. Jefferson Martinez takes readers on a richly detailed journey through centuries of cultural exchange, religious fervor, and military innovation. Through deep analysis of papal bulls, royal chronicles, military orders, and the vibrant cross-cultural tapestry of Christians, Muslims, and Jews, the book reveals how the grand European crusading ideals were adapted and uniquely transformed by the Iberian Christian kingdoms. From the sanctified battlefields where knights fought under the banner of Santiago Matamoros to the solemn halls where kings sought papal endorsement as defenders of the faith, this book explores the fusion of political ambition and spiritual devotion that fueled one of the longest and most complex conflicts in medieval Europe. It dismantles simplistic narratives, exposing a nuanced reality of diplomacy, coexistence, and contested identities that defined the Iberian frontier. Blending rigorous scholarship with vivid storytelling, The Influence of the Carolingian Empire and European Crusading Ideals on Iberia is an essential read for history enthusiasts, scholars, and anyone captivated by the interplay of faith, power, and war. Discover the origins of a legacy that shaped not only medieval Europe but the very foundations of Western identity.