Reference: W.s. 58
In 1563 a law was passed which instructed the bishops of the Welsh dioceses and the bishop of Hereford to arrange for the Bible and the Book of Common Prayer to be translated into Welsh by 1st March 1567. It was not until 1588 that Bishop William Morgan's translation of the whole Bible was published, but a translation of the Prayer Book was published on 6th May 1567, and a translation of the New Testament on 7th October in the same year. Both were published by Humfrey Toy and printed in London by Henry Denham.
Parts of the New Testament were translated by Richard Davies, Bishop of St. David's, and Thomas Huet, Cantor of St. David's, but most of the New Testament and the whole of the Prayer Book were the work of one translator, William Salesbury. Salesbury was born in Llansannan sometime before 1520 and spent most of his life in Llanrwst. He studied at Oxford University where he came under the influence of the Protestant Reformers, especially Erasmus, and decided to convert from his family's Catholic religion to Protestantism.
After the publication of the first book printed in Welsh, Yny lhyvyr hwnn by Sir John Prise (1546), William Salesbury was responsible for most of the books published in Welsh up to 1588. He was the author of the first Welsh dictionary, A dictionary in Englyshe and Welshe (1547). He was also responsible for the first publication of a substantial portion of the Scriptures to appear in Welsh, namely Kynniver llith a ban (1551), which is Salesbury's translation of the Gospels and Epistles read in the Church on Sundays. His other works included a collection of proverbs, an introduction to the Welsh language, an anti-Catholic book, and a translation of a classical work on astronomy.
The language of Salesbury's Testament is north Welsh, but he includes south Welsh forms in notes in the margins. His aim in his translation was to use scholarly vocabulary rather than everyday language, and he changed the spelling of Welsh words to make them more similar to Latin. Salesbury's language can therefore appear strange to modern readers, but his translation is an important milestone in the history of Welsh publishing and in the history of providing the people of Wales with the Scriptures in their own language. It was also the basis for William Morgan's translation of the whole Bible, the version which was used by the people of Wales with little change for the next four centuries.