Neil MacGregor's world history as told through things. This week he is exploring the development and co-existence of faiths across the globe around 400 years ago, looking at objects from India and Central America, Europe and Indonesia that embody the political consequences of belief. Today, he is with a remarkable object from Shia Iran that in the 16th century was open to the co-existence of faiths. The object he has chosen is a symbol of Shia faith, a standard or Alam that was carried at the front of Shia processions. They were often so tall and heavy that they would require great physical strength to handle. Neil visits religious sites in Isfahan to reflect on the spiritual climate of the time. Hossein Pourtahmasbi, from the Iranian community in London and a former alam carrier, describes the tradition. And the Iranian historian Haleh Afshar reflects on the shifting position of Shia Islam within Iran over the centuries. Producer: Anthony Denselow