Book excerpt: Hadrian's Wall is one of the world's best known legacies of the Roman Empire. It has stood for two thousand years as a moment to its creator, and yet he himself remains an enigmatic figure. Now bestselling author Danny Danziger and Nicholas Purcell reveal the details of the extraordinary life of this mysterious man, and the age in which he lived and ruled. Hadrian was Spanish, and a restless, inquiring intellectual. He travelled constantly and spent much time in cultural centres like Athens and Alexandria. Although he was not warlike, he was a good soldier, and was comfortable mingling amongst all ranks. And yet his personal life was a complicated one, rife with scandal and conflicted sexuality. This complex character was also responsible for some of the world's most enduring architectural treasures. He built the Pantheon in Rome, the largest dome built using pre-industrial methods and a sprawling 900-room villa at Tivoli with a towering 'pumpkin dome' - a fittingly idiosyncratic memorial to this most unusual of emperors.