Gregory the Great, Pope, [120], [121]
Guiscard, Robert, wars of, with Alexius I., [259-61]
Haroun-al-Raschid, wars of, with Nicephorus I., [203]
Helena, mother of Constantine I., [19]
Hellas, theme of, [168];
revolts against Leo III., [193]
Henry of Flanders, Emperor, [295-6]
Henry VI. of Swabia, Emperor of the West, [278]
Heracleonas, reign and fall of, [165-6]
Heraclius the Elder, rebellion of, [130]