This richly illustrated collection of essays examines for the first time the important Irish career of one of the most famous personalities of medieval Europe, William Marshal (c.1146-1219). The Marshal, with his wife Isabel de Clare, transformed the lordship of Leinster by the sword but also through the establishment of castles, churches, towns, and strategic infrastructure, as well as the institution of a new administrative framework that stabilised the Anglo-Norman colony. The essays in this book, by leading historians and archaeologists, present the Marshal in a new light–one that differs substantially from his better known persona as the ‘greatest knight that ever lived’ and a ‘flower of chivalry.