Knox and Picasso, on the face of it, couldn't be more different. Yet in their own way both proved to be world changers. One ushered the Reformation into 16th century Scotland, transforming the nation; the other refashioned art's age old rules in his own image and utterly changed how the 20th century looked. To mark the publication of a new biography of Knox and the recent £115 million record breaking sale of Picasso's The Women of Algiers, Professor Jane Dawson and Professor Elizabeth Cowling discuss how these two firebrands changed the world.