Welsh and Breton employ the Roman alphabet for writing. The oldest extant Welsh texts are from the 8th cent. A.D.

The Irish language is also sometimes referred to as Irish Gaelic and/or Erse. The history of Irish as a literary language falls into three periods: Old Irish (7th–9th cent. A.D.), Middle Irish (10th–16th cent.), and Modern Irish (since the 16th cent.). The alphabet employed today for Irish can be called a variant or a derivative of the Roman alphabet that took shape about the 8th cent. A.D. It has 18 letters: 13 consonants and 5 vowels. The oldest extant Irish texts are inscriptions written in the ogham script. These texts date back to the 5th cent. A.D. or perhaps earlier.

The earliest Irish manuscript, the Würzberg Codex, dates back to A.D. 700. The Amra Choluim Chille is believed to be a genuine sixth century manuscript and the Senchas Mór has also been placed in the sixth century by most experts.