This week, Neil MacGregor is exploring life in the great royal courts around the world during Europe's medieval period. It's easy to forget that the civilisations of Tang China, the Islamic Empire and the Maya in Mesoamerica were all at their peak during this time. He is describing the life of these courts through individual objects in the British Museum's collection. In the last programme he was with the Abbasid court North of Baghdad and an exotic wall painting; today's object is an engraved rock crystal connecting a biblical tale to a real life story of royal intrigue at the heart of Europe. The Lothair Crystal was made in the mid-ninth century and offers scenes in miniature from the biblical story of Susanna, the wife of a rich merchant who is falsely accused of adultery. The crystal was intended to exemplify the proper functioning of justice but, intriguingly, the king for whom the piece was made was himself trying to have his marriage annulled so he could marry his mistress! The historian Rosamond McKitterick explains what we know of the court of King Lothair and former senior law lord, Lord Bingham, describes the role of justice as portrayed in this exquisite work of art.Producer: Anthony Denselow