It is a vital source for knowledge of the Picts, as well as an insight into the life of Iona Abbey and the early medieval Gaelic monk.The vita of Columba contains a story that has been interpreted as the first reference to the Loch Ness Monster.Written just after or possibly contemporarily with Adomnán's Vita Columbae, the Vita Sancti Cuthberti (c.699–705) is the first piece of Northumbrian Latin writing and the earliest piece of English Latin hagiography.By the 9th century, Gaelic speakers controlled Pictish territory and Gaelic was spoken throughout Scotland and used as a literary language.However, there was great cultural exchange between Scotland and Ireland, with Irish poets composing for Scottish or Pictish patrons, and Scottish poets composing for Irish patrons.Gaelic literature in Scotland includes a celebration, attributed to the Irish monk Adomnán, of the Pictish King Bridei's (671–93) victory over the Northumbrians at the Battle of Dun Nechtain (685).Pictish, the now extinct Brythonic language spoken in Scotland, has left no record of poetry, but poetry composed in Gaelic for Pictish kings is known.
In Medieval Welsh literature the period before 1100 is known as the period of Y Cynfeirdd ("The earliest poets") or Yr Hengerdd ("The old poetry").
Changing consciousness of English national identity, Scottish national identity, Welsh nationalism, and the effects of British imperialism have altered interpretations of how the literatures of Britain have interacted.
In addition the impact of Irish nationalism, that led to the partition of the island of Ireland in 1921, means that literature of the Republic of Ireland is not British, although the identity of literature from Northern Ireland, as part of the literature of the United Kingdom, may fall within the overlapping identities of Irish and British literature, where "the naming of the territory has always been, in literary, geographical or historical contexts, a politically charged activity".
Literature in Northern Ireland includes writings in English, Irish and Ulster Scots.
Irish writers have played an important part in the development of literature in England and Scotland, but though the whole of Ireland was politically part of the United Kingdom between January 1801 and December 1922, it is controversial to describe Irish literature as British.
The literary Gaelic language used in Scotland that was inherited from Irish is sometimes known as Classical Gaelic.