Bible translations into Welsh have existed since at least the 15th century, but the most widely used translation of the Bible into Welsh for several centuries was the 1588 translation by William Morgan, as revised in 1620. The Beibl Cymraeg Newydd was published in 1988 and revised in 2004. Beibl.net is a new translation in colloquial Welsh which was recently completed.
Several 19th century sources mention that a translation from the Latin Vulgate was in existence in 1470: for example Bishop Richard Davies claimed to have seen, as a boy, such a translation in a manuscript in the house (named Celydd Ifan) of an uncle. However, Professor Glanmor Williams dismisses the theory that the whole Bible had been translated into Welsh before William Morgan's Bible appeared in 1588.
Following the English Reformation, translations were made from the Greek versions. The New Testament translation of William Salesbury was printed in 1567 by Humphrey Toy.
Salesbury's New Testament was followed by William Morgan's translation of the whole Bible in 1588. Morgan soon began work on a revision of his 1588 Bible, which contained a number of printing errors (or on a new translation). After Morgan's death, Bishop Richard Parry and Dr John Davies continued the work with the aims of polishing the literary language, replacing forms considered too colloquial, and bringing the text into greater conformity with the King James Version of the English Bible of 1611. The revised version of the Bible was published in 1620. This edition is still known as William Morgan's translation, and it is this rather than the previous edition which was the standard Welsh Bible until the late 20th century, and continues to be used to this day. It occupies a similar place in the Welsh language to that of the venerated King James Version in English.