The recorded story of Scotland begins with the arrival of the Roman Empire in the 1st century, when the province of Britannia reached as far north as the Antonine Wall. But how much further back can the history of Scotland be traced? Who were the Picts and the Gaels? And how did the Viking invasion unite them? Rob Weinberg asks the big how and why questions about the birth of Scotland to Dr. Alex Woolf, senior lecturer at the University of St Andrews.