<p>'King's supreme ability is to imagine himself into the past. The scope of his knowledge is staggering' JOHN CAREY, SUNDAY TIMES<br>At its largest extent, the Roman Empire stretched from the Persian Gulf to the Irish Sea, from North Africa to central Europe. A fifth of the world's population were Roman<br>citizens. Even after the empire's dramatic decline and fall, its legacy continued to shape politics and laws, language and numerals, calendar...