(4) As a natural precaution for the defence of Bavaria, Charles then turned against the Avars, a race akin to the Huns, who had settled on the middle Danube after the departure of the Lombards for Italy. The Avars invaded Bavaria and Friuli as allies of Tassilo (788); they were punished by three campaigns of extirpation (791-796), which broke their power and spared only a miserable remnant of their people. Their land was annexed but not settled; for Germany offered a more tempting field to the Frankish pioneers. Indeed, some of the surviving Avars were planted in the Ostmark (Austria), which Charles established as an outpost of Bavaria, to keep watch upon the Slavs. (5) To Spain the Emperor first turned his attention in 777, when he was invited by the discontented emirs on the north of the Ebro to free them from the Caliph of Cordova. The next year saw his abortive march through the pass of Roncesvalles to the walls of Saragossa--an expedition immortalised in the _Chanson de Roland_, the earliest and most famous epic of the Charlemagne cycle, but fabulous from first to last, except in recording the fact that there was a certain Roland (warden of the Breton Mark) who fell in the course of the Frankish retreat. More substantial work was done in Spain during the last years of the reign. Navarre declared for the Franks and Christianity; the eldest son of Charles captured Tortosa at the mouth of the Ebro (811), and founded the Spanish Mark. This lengthy catalogue only accounts for the more important of the wars in which Charles and his lieutenants were engaged. We must imagine, to complete the picture, a background of minor conflicts within and without the Empire--against the Slavs, the Danes, the Greeks, the Bretons, the Arabs, the Lombards of Benevento. These crowded years of war leave the Frankish Empire established as the one great power west of the Elbe and Adriatic. It did not include the Scandinavian lands or British Isles; the Franks were never masters of the northern seas. It had failed to expel the Arabs and Byzantines from the western Mediterranean; Spain, Sicily, even parts of Italy remain unconquered. Of recovering North Africa there could be no question. Still in magnitude the Frankish realm was a worthy successor of the Western Empire. On Christmas Day, 800, Charles was crowned Emperor of the Romans by Pope Leo III, in St. Peter's basilica at Rome; and his subjects vainly imagined that, by this dramatic ceremony, the clock of history had been put back four hundred years. Though the Age of the Barbarians had been ended by the greatest of them, the era which he inaugurated was an era not of revival but of new development. III THE EMPIRE AND THE NEW MONARCHIES (800-1000 A.D.)