Welsh nationalism (Welsh: Cenedlaetholdeb Cymreig) emphasises and celebrates the distinctiveness of Welsh culture and Wales as a nation or country. Welsh nationalism may also include calls for further autonomy or self-determination, which includes Welsh devolution, meaning increased powers for the Senedd, or full Welsh independence.
Welsh devolution is the transfer of legislative powers for self-governance to Wales by the Parliament of the United Kingdom. The current system of devolution began following the enactment of the Government of Wales Act 1998, with the responsibility of various devolved powers granted to the Welsh Government rather than being the responsibility of the Government of the United Kingdom.
Wales was conquered by England during the 13th century, with the Laws in Wales Acts 1535 and 1542 applying English law to Wales and incorporating it into England (survives as the England and Wales legal jurisdiction), and later into Great Britain and the United Kingdom. A rise in Welsh nationalism and political movements advocating for Welsh autonomy became more prominent in the late nineteenth century. The devolution of some administrative responsibilities began in the early twentieth century, as well as the passing of laws specific to Wales. Since World War II, various movements and proposals have advocated different models of Welsh devolution.
The 1966 Carmarthen by-election, was held in Carmarthen, Wales, on 14 July 1966. The contest was significant in that it resulted in the election of Gwynfor Evans, the first ever Plaid Cymru member of parliament. Plaid Cymru's victory in the Carmarthen constituency, a seminal moment for Welsh nationalism, was part of a wider process toward Welsh devolution which eventually led to the establishment of the Welsh Assembly in 1999.
The election was caused by the death of Labour Party member of parliament Megan Lloyd George.