Although the Welsh language and its ancestors have been spoken in what is now Wales since well before the Roman incursions into Britain, historian John Davies argues that the origin of the "Welsh nation" can be traced to the late 4th and early 5th centuries, following the Roman departure.
Meskipun bahasa Wales dan nenek moyang bangsa Wales telah ada di tempat yang sekarang menjadi Wales sejak sebelum serangan Romawi ke Britania, sejarawan John Davies berpendapat bahwa asal usul "bangsa Wales" dapat ditelusuri sampai akhir abad ke-4 dan awal abad ke-5, setelah kepergian bangsa Romawi.