History
Old Briton is descended from Proto-Celtic, a hypothetical parent language. By the first half of the first millennium BC it was already dividing into separate dialects or languages. There is some evidence that the Pictish language may have had close ties to Old Briton and might be a fifth branch.
Evidence from Welsh shows a great influence from Latin on Old Briton during the Roman domain. This is particularly true of the Church and Christianity, which are nearly all Latin derivatives. Old Briton was replaced in most of Scotland by Old Irish. South of the Firth of Forth it was replaced by Old English. Old Briton survived into the Mid-Ages in South Scotland and Cumbria. Old Briton was gradually replaced by English throughout England. In the north of England, Cumbric disappeared as late as the 13th century. In the south, the Cornish was a dead language by the 19th century. There were some attempts to revitalize it, which have met with some success.