Neil MacGregor's world history as told through things. This week he is exploring the sophisticated ways that people expressed religious yearning in the 14th and 15th centuries. He is looking at the statues of gods and ancestors - in India, Mexico and on Easter Island - and he describes the importance of icon painting in the Orthodox Church. Today he is with an object designed to connect with Christ himself - a stunning Christian reliquary from medieval Europe made to house a thorn from the crown of thorns. Neil tells the story of this highly ornate reliquary while Sister Benedicta Ward and the Archbishop of Leeds, the Right Reverend Arthur Roche, help explain the background and meaning to the powerful tradition of relic worship.Producer: Anthony Denselow