Parts of the Bible were translated into Welsh before the fifteenth century, but the first complete translation was the manuscript of Celydd Sfan, while no exact date for its compositiion is known it was in existence by 1470.

This was a translation from the Latin Vulgate. Following the Reformation translations were made from the Greek versions. The New Testament translation of William Salesbury was printed in 1567, closely followed by William Morgan's translation of the whole Bible in 1588.