If the medieval king was the helmsman of the ship of state, the royal household was the ship's engine. It comprised men from most ranks of society, from the great magnates of the realm to simple servants who looked after the day-to-day needs of the king and his court. This is the first full-length study of the most important group of the court household, the king's knights: socially élite, militarily preeminent, and indispensable for the workings of English medieval government.