But to the north and west of the Wash the Danes obtained a very different footing. In the province called Mercia (or the Marches), which formed the centre of England, and in that of Lindisse (or, in old Norsk, Lindisey), which extended from the Wash to the Humber, they were not only in possession of a great number of villages and landed estates, which they had selected to settle on, but had likewise made themselves masters of several towns, and particularly the five strong fortresses of Stamford, Leicester, Derby, Nottingham, and Lincoln. These places, which as early as Alfred’s reign belonged to the Danes, and which were distinguished by their size, their commerce, and their wealth, obtained the name of “The Five Burghs” (Femborgene). They formed, as it were, a little separate state, and possessed in common their own courts of judicature, and other peculiar municipal institutions. The hostile and dangerous neighbourhood of the Saxons naturally compelled them to coalesce together as much as possible; and for a very long period they formed the chief support of the Danish power in England. Protected by them from all attacks from the south, the Scandinavian settlers were enabled securely to continue establishing themselves in the more northern districts. To arrest the sudden attacks of the Britons in the west, the Danes also had, on the north-eastern frontier of Wales, the city of Chester, whose name (_Anglo-Saxon_, Lægeceaster, from the Latin castra, a camp) shows that it had been a fortified place still earlier, under the Romans. Chester formed one of the principal entrances from Wales into the midland parts of England, as well as into what was then called Northumberland: under which name was comprised, at least by the Danes and Norwegians, all the country to the north of the rivers Mersey and Humber, from sea to sea, and up to the Scottish frontier. Covered by the “Five Burghs,” it was here that the greater part of Danish England lay. It was a country filled, particularly in the north-west, with mountains, and intersected by numerous rivers. Near these, valleys opened themselves in every direction, of which the largest and most considerable lay around the tributary streams of the Humber, in what is now Yorkshire. A separate kingdom had existed here from the oldest times; and here the Danes, like the Britons, the Romans, and the Anglo-Saxons before them, possessed the most important city in the north of England. Built on the river Ouse, which falls into the Humber, it carried on an extensive trade; and, as the principal seat of the Northumbrian kings and chiefs, was doubly important. The Britons called it “Caer Eabhroig,” or “Eabhruc,” the Romans “Eboracum,” the Anglo-Saxons “Eoforwic,” and the Danes “Jorvik;” whence it is plain that the form “York,” now in use, is derived.