The Dark Ages have been misunderstood. History has identified the period following the fall of the Roman Empire with a descent into barbarism - a terrible time when civilisation stopped. Waldemar Januszczak disagrees. In this four-part series he argues that the Dark Ages were a time of great artistic achievement, with new ideas and religions provoking new artistic adventures. He embarks on a fascinating trip across Europe, Africa and Asia, visits the world's most famous collections and discovers hidden artistic gems, all to prove that the Dark Ages were actually an 'Age of Light'.