"When Leif the Lucky and his Viking explorers linked Europe and America with their settlement at Vinland it marked a profound change in the world. Suddenly, almost every region on earth was in touch with its neighbours, spanning continents and oceans. For a few years, it was in theory possible to send a message all the way round the world. At the time, no one could possibly have known this, or what it would lead to. But in hindsight the early 11th century gives us a brief hint of today’s global unity. But what was the world like 1,000 years ago?