[209] Gregory IV. (827-844) was succeeded in the papal office by Sergius II. (844-847).
[210] By the treaty of Verdun in 843 Charles the Bald had been given Aquitaine, along with the other distinctively Frankish regions of western Europe. His nephew Pepin, however, who had never been reconciled to Charles's taking possession of Aquitaine in 838, called himself king of that country and made stubborn resistance to his uncle's claims of sovereignty [see p. [156]].
[211] The Wends were a Slavonic people living in the lower valley of the Oder.
[212] By "the heathen" are meant the Norse pirates from Denmark and the Scandinavian peninsula. On their invasions see [p. 163].
[213] This Saracen attack upon Rome was made by some Arab pirates who in the Mediterranean were playing much the same rôle of destruction as were the Northmen on the Atlantic coasts. A league of Naples, Gaeta, and Amalfi defeated the pirates in 849, and delivered Rome from her oppressors long enough for new fortifications to be constructed. Walls were built at this time to include the quarter of St. Peter's—a district known to this day as the "Leonine City" in memory of Leo IV., who in 847 succeeded Sergius as pope [see above text under date 850].
[214] Fulda was an important monastery on one of the upper branches of the Weser, northeast of Mainz.
[215] An octave, in the sense here meant, is the week (strictly eight days) following a church festival; in this case, the eight days following the anniversary of Christ's birth, or Christmas.
[216] The isle of Rhé, near Rochelle, north of the mouth of the Garonne.
[217] Galicia was a province in the extreme northwest of the Spanish peninsula.
[218] Charles the Bald, who by the treaty of Verdun in 843, had obtained the western part of the empire built up by Charlemagne [see [p. 154]].