Plaid Cymru, the Party of Wales, was founded in Llandudno in 1925 as a response to the perceived threat of the Welsh language's extinction. At that time, the use of Welsh was declining, with English becoming the dominant language in many aspects of public life, education, and media. The formation of Plaid Cymru was driven by influential figures including Lewis Valentine, who sought to unite individuals committed to the revival of the Welsh language and culture. The party's foundational objectives included promoting Welsh language education, broadcasting, and literature, alongside advocating for the political rights of the Welsh people.

The creation of Plaid Cymru was a significant milestone in the assembly of a political movement focused on national identity and cultural preservation. Between the 1920s and 1950s, the party faced numerous challenges, including engaging with an Anglophone dominated political system and garnering support from the broader Welsh population. Moreover, it sought to make the Welsh identity known not only within Britain but also internationally, embracing themes of independence and self-governance.

As Plaid Cymru began to gain traction, members organized events and campaigns to raise awareness of the Welsh language's plight. Initiatives focused on promoting Welsh in schools and public life, reflecting a broader desire for cultural appreciation and linguistic revitalization. By using politics as a vehicle for change, the party laid the groundwork for future generations to reclaim their linguistic heritage, fostering a sense of pride and belonging among Welsh speakers.