The settlem ent of Prussia by the Teutonic O rder was by no means the only venture of G erm an colonization in the east. Charlem agne’s, successful subjugation of the Saxons may be considered one of the earliest moves of eastern expansion. This took the Germans to the river Elbe, an ideal position from which to penetrate further eastward. There were several marches of the Reich, established for protection against the heathens such as the Wends and the Slavs. The m archer territory of Brandenburg, the M ark Brandenburg, was one of these, its origin lying in the period of Charlem agne’s reign. It was subdivided into various parts, the m ost im portant of which, alm ost coinciding in terms of territory with the later M ark Brandenburg, was the N ordm ark. This consisted of all the German-colonized territories on the west bank of the river Elbe, later to be called the A ltm ark. From the A ltm ark trade developed with the W endish neighbours; it formed the base of power and supplies for war with them, as well as m issionary activity. Already in the tenth century, under O tto the Great, two dioceses were established in Havelberg and Brandenburg, supervised by the bishopric of M agdeburg which had been founded in 968. An uprising of the Wends against their new m asters and new religion had put a tem porary end to these dioceses, and it was only in the twelfth century, as part of the general crusading fervour and the beginnings of a further G erm an movement eastwards in which the Teutonic Knights were later to take part, tha t G erm an settlem ent east of the Elbe was firmly re-established. This process of colonization of the east had basically little to do with imperial policy, whose focus of political and m ilitary a ttention lay to the south of Germany, in Italy. R ather it was the policy of several of the G erm an territorial princes, notably Henry the Lion, who, as vassal of Frederick Barbarossa, fell out with him when he refused to support the crusade to the Holy Land, seeing his prim ary mission within Germany and its eastern expansion.