he claimed to have found; these are regarded as Williams's first forgeries. His success led him to return to London in 1791, where he founded the Gorsedd, a community of Welsh bards, at a ceremony on 21 June 1792 at Primrose Hill. He organised the occasion according to what he claimed were ancient Druidic rites. In 1794 he published some of his own poetry, which was later collected in a two-volume Poems, Lyric and Pastoral. Essentially his only genuine work, it proved quite popular. Williams worked with Owen Jones and William Owen Pughe on The Myvyrian Archaiology of Wales, a three-volume collection of medieval Welsh literature published in 1801–1807. This relied partly on manuscripts in Williams's collection, some his forgeries. The forged material included a false Brut chronicle and a book attributed to Saint Cadoc. The second volume, which collected the Welsh Triads, contained an additional "third series" of forged triads, as well as Williams's alterations to the authentic ones. After Williams's death some of his collection was compiled into The Iolo Manuscripts by his son, Taliesin Williams. His papers were used by many later scholars and translators, and for reference by Lady Charlotte Guest as she translated the prose collection Mabinogion. She did not, however, rely on William's editions of the tales themselves, except for Hanes Taliesin. Later still, further Williams forgeries were published in a text known as Barddas. This work, published in two volumes in 1862 and 1874, was claimed to be a translation of works by Llywelyn Siôn, detailing the history of the Welsh bardic system from its ancient origins to the present day. Though it contains nothing of authentic Druidic lore, it is the fullest account of the mystical cosmology Williams developed. Other works by Williams include the "Druid's Prayer", still used by the Gorsedd and by neo-Druid groups, a treatise on Welsh metrics called Cyfrinach Beirdd Ynys Prydain ("The Mystery of the Bards of the Isle of Britain"), published posthumously in 1828, and a hymn series published as Salmau yr Eglwys yn yr Anialwch ("Psalms of the church in the wilderness") in 1812. Philosophy Iolo's philosophy represented a fusion of Christian and Arthurian influences, a romanticism comparable to that of William Blake and the Scottish poet and forger James MacPherson, the revived antiquarian enthusiasm for all things "Celtic", and such elements of bardic heritage as had genuinely survived among Welsh-language poets. Part of his