The Viking invasion forced the dialect to split in two. The southern Northumbrian dialect was heavily influenced by Norse. The northern Northumbrian dialect not only retained a lot of the Old English words (replaced in the south by Norse words) but was also a strong influence on the development of the English language in northern England, especially the dialects of modern North east England and Scotland.
Examples of the first English literature include Christ's Prayer in Old English from c. 650, which begins "Faeder ure, Thu the eart on heofonum,". Some Scottish and Northumbrian folk still say /uːr 'feðər/ or /uːr 'fɪðər/"our father" and [ðu: e:rt] "thou art".1
FADER USÆR ðu arðin heofnu
Sie gehalgad NOMA ÐIN.
Tocymeð RÍC ÐIN.
Sie WILLO ÐIN
suæ is in heofne and in eorðo.
HLAF USERNE of'wistlic sel ús todæg,
and f'gef us SCYLDA USRA,
suæ uoe f'gefon SCYLDGUM USUM.
And ne inlæd usih in costunge,
ah is in heofne and in eorðo.
The best examples of modern Northumbrian can be found in the dialects of the traditional counties of Northumberland and County Durham, or more specifically the Geordie and Mackem dialects where many words are still retained. Another would be the Scots Language as spoken in southern Scotland.
