The Normans had an astonishingly good run. Not only did they take over England in 1066, of course, but they also triumphed over the Muslims, establishing themselves in southern Italy and founding a principality in the Near East. William the Conqueror’s is one of the most famous names from Europe’s Middle Ages, but the achievements of Robert Guiscard were nearly as astonishing: leaving Normandy with five knights and 30 infantrymen, he became Duke of Sicily, Apulia and Calabria.