Whilst in London Kyffin enjoyed singing the psalms in the Church of England tradition. He wanted to translate the Welsh psalms into metre, so that they could be sung as the English metrical psalms were. It is believed that he versified around 50 of the psalms from William Morgan's Welsh translation, but only a handful have survived. The surviving psalms were collected by Thomas Salisbury. In 1603 he had them published in London by the printer Samuel Stafford, as: "Rhann o Psalmae Dafydd Brophwyd - iuu canu ar ôl y dôn arferedig yn Eglwys Loegr." This includes 12 full psalms and the first 5 verses of Psalm 13. These are set in 4 line stanzas, set to the traditional Welsh poetic style known as "awdl gywydd".