Even had Charlemagne been followed by strong and able rulers, it would have been a difficult matter to hold the empire together in the face of the fresh series of barbarian inroads which began immediately after his death. The Mohammedans, though checked by the Franks at the battle of Tours, [18] continued to be dangerous enemies. They ravaged southern France, Sicily, and parts of Italy. The piratical Northmen from Denmark and Norway harried the coast of France and made inroads far beyond Paris. They also penetrated into western Germany, sailing up the Rhine in their black ships and destroying such important towns as Cologne and Aix-la- Chapelle. Meanwhile, eastern Germany lay exposed to the attacks of the Slavs, whom Charlemagne had defeated but not subdued. The Magyars, or Hungarians, were also dreaded foes. Their wild horsemen entered Europe from the plains of Asia and, like the Huns and Avars to whom they were probably related, spread devastation far and wide. A great part of Europe thus suffered from invasions almost as destructive as those which had brought ruin to the old Roman world. 109. GERMANY UNDER THE SAXON KINGS, 919-973 A.D. THE GERMAN STEM-DUCHIES The tenth century saw another movement toward the restoration of law and order. The civilizing work of Charlemagne was taken up by German kings, not of the old Prankish stock, but belonging to that Saxon people which had opposed Charlemagne so long and bitterly. Saxony was one of the five great territorial states, or stem-duchies, as they are usually called, into which Germany was then divided. [19] Germany at that time extended only as far east as the river Elbe, beyond which lay the territory occupied by half-civilized Slavic tribes. ELECTIVE KINGSHIP OF GERMANY The rulers of the stem-duchies enjoyed practical independence, though they had recognized some king of Germany ever since the Treaty of Verdun. Early in the tenth century the Carolingian dynasty died out in Germany, and the German nobles then proceeded to elect their own kings. Their choice fell first upon Conrad, duke of Franconia, but he had little authority outside his own duchy. A stronger man was required to keep the peace among the turbulent nobles and to repel the invaders of Germany. Such a man appeared in the person of Henry, duke of Saxony, who, after Conrad's death, was chosen king. REIGN OF HENRY THE FOWLER, 919-936 A.D. Henry I, called the Fowler, because he was fond of hunting birds, spent the greater part of his reign in wars against the Slavs, Magyars, and other invaders. He conquered from the Slavs the territory afterwards known as Brandenburg. This country was to furnish Germany, in later centuries, with its present dynasty--the Hohenzollerns. [20] He occupied the southern part of Denmark (Schleswig) and Christianized it. He also recovered for Germany Lorraine, a district which remained in German hands until the eighteenth century. REIGN OF OTTO THE GREAT, 936-973 A.D.