However, this move, and the party's early attempts to develop an economic critique, did not broaden its appeal beyond that of an intellectual and socially conservative Welsh language pressure group.

[66] The alleged sympathy of the party's leading members (including President Saunders Lewis) towards Europe's totalitarian regimes compromised its early appeal further.

The leaders' treatment, including the trial judge's dismissal of the use of Welsh and their subsequent imprisonment in Wormwood Scrubs, led to "The Three" becoming a cause célèbre.

[64][68] Penyberth, and Plaid Cymru's neutral stance during the Second World War, prompted concerns within the UK Government that it might be used by Germany to insert spies or carry out other covert operations.

In the 1945 general election, with party membership at around 2,500, Plaid Cymru contested seven seats, as many as it had in the preceding 20 years, including constituencies in south Wales for the first time.

Proposals to flood the village of Capel Celyn in the Tryweryn valley in Gwynedd in 1957 to supply the city of Liverpool with water played a part in Plaid Cymru's growth.

Gwynfor Evans lost Carmarthen to Labour, but regained the seat in October 1974, by which time the party had gained a further two MPs, representing the constituencies of Caernarfon and Merionethshire.

[citation needed] Plaid Cymru's emergence (along with the Scottish National Party) prompted the Wilson government to establish the Kilbrandon Commission on the constitution.

Despite Plaid Cymru's ambivalence toward home rule (as opposed to outright independence) the referendum result led many in the party to question its direction.

[65] Plaid campaigned to leave the Common Market in the 1975 referendum,[76][77] feeling that the EC's regional aid policies would "reconcile places like Wales to their subordinate position".

[citation needed] Caernarfon MP Dafydd Wigley succeeded Gwynfor Evans as president in 1981, inheriting a party whose morale was at an all-time low.

[81] While the party embarked on a wide-ranging review of its priorities and goals, Gwynfor Evans fought a successful campaign (including the threat of a hunger strike) to oblige the Conservative government to fulfill its promise to establish S4C, a Welsh-language television station.

[citation needed] In the 1992 general election, the party added a fourth MP, Cynog Dafis, when he gained Ceredigion and Pembroke North from the Liberal Democrats.

[83] Ahead of the 1999 National Assembly for Wales election, Plaid Cymru dropped its policy of Welsh independence in favour of continued membership in the European Union.

The ensuing leadership battle, won by Alun Michael, did much to damage Labour, and thus aided Plaid Cymru, whose leader was the more popular and higher profile Dafydd Wigley.

[85] Less than two months later, in elections to the European parliament, Labour support slumped further, and Plaid Cymru came within 2.5% of achieving the largest share of the vote in Wales.

[84] The 2004 local election saw the party lose control of the two South Wales councils it gained in 1999, Rhondda Cynon Taff and Caerphilly, while retaining its stronghold of Gwynedd in the north-west.

[89] Since Plaid Genedlaethol Cymru reformation to 'Plaid Cymru' in 1933, the logo representing the party was the green 'triban' (three peaks) which symbolically represented Plaid's three key goals; self-government, cultural prosperity and economic prosperity, 'anchored in the bedrock of Welsh identity and history that is the Welsh upland landscape',[90] the logo would change in the late stages of 20th century to include the red dragon of Wales, however this version was short-lived.

[citation needed] After weeks of negotiations involving all four parties in the Assembly, Plaid Cymru and Labour agreed to form a coalition government.

[citation needed] In the 2011 National Assembly election, Plaid slipped from second place to third, being overtaken by the Welsh Conservatives and losing its deputy leader Helen Mary Jones.

[97] A leadership election was held in which three candidates eventually stood: Elin Jones, Dafydd Elis-Thomas and Leanne Wood;[98] Simon Thomas withdrew his candidacy before ballots were cast.

[41][101] Soon after her election as leader, she appointed former MP Adam Price to head an economic commission for the party "focussed on bringing together tailor-made policies in order to transform our economy".

[104] On 12 November 2012, Wood announced she would aim to abandon her relatively safe list seat by winning a constituency at the 2016 National Assembly elections;[105] she later confirmed she would contest the Rhondda.

[119] In September 2018, Adam Price won the party's leadership election, defeating the incumbent Leanne Wood and fellow challenger Rhun ap Iorwerth.

It launches us on a pathway to a united Wales, one that, sooner than we perhaps think, will find it both comfortable and natural, indeed essential, to join the world community of normal, independent nations.

There will be stability payments to support family farms; exploration of an accelerated pathway to net zero by 2035; the creation of Ynni Cymru – a company to expand community-owned renewable energy generation; and a new and reformed Senedd – bigger, more diverse, and gender balanced in law.

Acknowledging that he "no longer had the united support of [his] colleagues", Price stated that he would step down officially at the start of the following week, once the process for electing a new interim leader was finalised.

[137][138] On 11 May Plaid Cymru announced that Llyr Gruffydd, Senedd member for North Wales, would replace him as interim party leader, and that this would be confirmed by the NEC on 13 May.

[146] In December 2020, Price stated that an independence referendum would be held in Plaid Cymru's first term in office, if the party won a majority at the 2021 Senedd election.

*Six seats (Blaenau Gwent, Ceredigion & Pembroke North, Islwyn, Monmouth, Newport West and Torfaen) contested on a joint Plaid Cymru/Green Party ticket *The 2012 figures exclude Anglesey, where the vote was delayed until 2013.