The Knights Templar are history's most mythologized military order — simultaneously celebrated as crusading warriors, condemned as heretics, and claimed as ancestors by everyone from Freemasons to modern conspiracy theorists. Beneath the mythology lies something more historically remarkable: a organization that invented sophisticated financial instruments, operated the medieval world's first international banking network, and accumulated enough institutional power to make the King of France feel threatened enough to destroy them. This book examines the Templars as a historical institution rather than a romantic legend. It traces their origins in the aftermath of the First Crusade, their evolution from a small protective brotherhood into a transnational financial and military corporation, and the specific banking innovations — letters of credit, deposit accounts, interest-bearing loans — that made them indispensable to monarchs, merchants, and pilgrims across three continents. It reconstructs the political machinery behind Philip IV's suppression campaign of 1307, examining how debt, ambition, and papal weakness combined to dismantle Europe's most powerful private institution. Drawing on papal archives, Templar trial records, and medieval financial history, this is a rigorous account of an organization whose actual legacy — the architecture of modern banking — is far more consequential than any hidden treasure.