Although the Norse conquered and settled areas in northern England, northern France, Russia, Ireland, Scotland, the Orkneys, Iceland, Greenland, and even settled as far as North America in the west and Byzantium in the east, only Iceland and Normandy in the north of France became permanent, lasting polities under the Norse settlers.
The Norse who had the temerity to sail west beyond the coast of England found an island warmed by vulcanism and the Gulf Stream that was ripe for the picking.
It was among Icelanders that Norse religion held on the longestthe Icelanders were not converted to Christianity until 1000 when the Norwegian king, Olafr Tryggvason, sent missionaries to Iceland and held several Icelanders hostage in order to force conversions.
During this early period it assimilated some aspects of the languages with which it came in contact, such as the Celtic languages and the two dialects of Old Norse from the invading Vikings, who were occupying and controlling large tracts of land in northern and eastern England, which came to be known as the Danelaw.
Some of these features were specific to the West Germanic language family to which Old English belongs, while some other features were inherited from the Proto-Germanic language from which all Germanic languages are believed to have been derived.
Like other West Germanic languages of the period, Old English was fully inflected with five grammatical cases, which had dual plural forms for referring to groups of two objects (but only in the personal pronouns) in addition to the usual singular and plural forms.