The 'Gramadegyddion' (Grammarians) were a group of poets responsible for the cultural revival in Glamorgan during the eighteenth century. Like their counterparts in north Wales and London, they depended on books published by Welsh humanists and contemporary revivalists in order to reclaim their poetic heritage. They called themselves Grammarians in deference to the published poetic grammars which had enabled them to achieve this aim: Siôn Dafydd Rhys's Cambrobrytannicae Cymraecaeve Linguae Britannicae . . . Rudimenta (1592), William Midleton's Bardhoniaeth, neu brydydhiaeth (1593), and John Rhydderch's Grammadeg Cymraeg (1728). Based largely in the Uplands of Glamorgan, the Grammarians held occasional eisteddfodau modelled on those held in north Wales in the early part of the eighteenth century. The group included men who would later play key roles in Iolo's bardic vision: John Bradford of Betws, Rhys Morgan of Pencraig-nedd, Edward Evan of Aberdare, Dafydd Nicolas of Aberpergwm, and Iolo's tutor in strict-metre poetry, Lewis Hopkin of Llandyfodwg. Other members included Dafydd Hopcyn of Coety, Dafydd Thomas of Pandy'r Ystrad and, possibly, the poet who became a romantic figure in local folklore, Wil Hopcyn of Llangynwyd. Many of these men were craftsmen and Dissenters, and Iolo later referred to them as a circle of freethinkers called 'Gwŷr Cwm y Felin' (Men of the Mill Valley). Iolo's poetic, antiquarian, philosophical and cultural interests were not cultivated in a vacuum. The Grammarians, like their counterparts in north Wales, understood the power of the printing press and published works of poetry and theology. In this respect they established a pattern for Iolo and gave him a strong motive to publish his own works.