In this lecture Dr William Purkis will explore how and why the rulers of the twelfth-century kingdom of Jerusalem expressed their devotion to two of the most valuable sacred treasures within their custody: the Holy Sepulchre and the True Cross. Through close examination of a range of medieval objects, including coins, documentary seals and illuminated manuscripts, as well as a variety of post-medieval artefacts, the lecture will illustrate the importance of the Museum’s collections for understanding this fascinating period of medieval history.