Excerpt from: "Welsh Poetry" by Douglas Houston in A Companion to 20th Century Poetry

"With regard to the internal cultural identity of Wales, the canon of Welsh poetry in English, or Anglo-Welsh poetry as it is often termed, has emerged during the twentieth century. Such earlier poets as Henry Vaughan, George Herbert and John Dyer have strong claims to being Welsh, but their works belong primarily in the English poetic tradition. Welsh remained the pre-eminent language of poetry within Wales until the end of the nineteenth century. The establishment of Welsh poetry in English as an internal literature of Wales followed the fading of the social and cultural order initiated in the mid-eighteenth century by the Methodist Awakening. Industrialism and the demographic shifts it effected displaced Welsh as the language of the majority in the more densely populated regions." 

Poets

Dylan Thomas
Gwyneth Lewis
R.S. Thomas