This article is about the particular significance of the decade 1820 - 1829 to Wales and its people.
Prince of Wales - George (until 29 January 1820) (became George IV)
Princess of Wales - Caroline of Brunswick (until 29 January 1820)
John Elias - Golygiad Ysgrythurol ar Gyfiawnhad Pechadur (1821)
Felicia Hemans - The Forest Sanctuary (1825)
Thomas Price (Carnhuanawc) - An Essay on the Physiognomy and Physiology of the Present Inhabitants of Britain (1829)
David Richards (Dafydd Ionawr) - Cywydd y Dilyw (1821)
John Ellis - Eliot (hymn tune) (1823)
Edward Jones - Hen Ganiadau Cymru (1820)
Peroriaeth Hyfryd (collection of hymns including Caersalem by Robert Edwards) (1827)
Seren Gomer (collection of hymns including Grongar by John Edwards) (1824)
1820
21 May - Sir Thomas Lloyd, 1st Baronet, politician and landowner (d. 1877)
1821
24 June - Guillermo Rawson, Argentinian politician (d. 1890)
16 July - John Jones (Mathetes), preacher and writer (d. 1878)
1822
2 March - Michael D. Jones, Patagonian settler (d. 1898)
1823
8 January - Alfred Russel Wallace, biologist (d. 1913)
March - Rowland Williams (Hwfa Môn), poet and archdruid (d. 1905)
23 November - Sir John Evans, archaeologist (d. 1908)
1824
date unknown - John Basson Humffray, political reformer in Australia (d. 1891)
1825
7 June - R. D. Blackmore, novelist (d. 1900)
1826
13 January - Henry Matthews, 1st Viscount Llandaff (d. 1913)
1 March - John Thomas, harpist (d. 1913)
8 May - George Osborne Morgan, lawyer (d. 1897)
11 May - David Charles Davies, Nonconformist leader (d. 1891)
1827
27 October - Joseph Tudor Hughes (Blegwryd), harp prodigy (d. 1841)
1828
30 January - John David Jenkins, philanthropist (d. 1876)
1829
27 January - Isaac Roberts, astronomer (d. 1904)
1820
29 January - King George III of the United Kingdom, Prince of Wales 1751-1760
16 June - Thomas Jones of Denbigh, Methodist preacher and writer (b. 1756)
27 June - William Lort Mansel, bishop and academic (b. 1753)
23 August - John Randles, harpist (b. 1763)
28 August - Henry Mills, musician (b. 1757)
1821
2 May - Hester Thrale, diarist (b. 1741)
7 August - Caroline of Brunswick, former Princess of Wales (1795-1820), 53
1822
30 March - David Thomas (Dafydd Ddu Eryri), poet (b. 1759)
date unknown - Stephen Kemble, actor, brother of Sarah Siddons (b. 1758)
1823
26 February - John Philip Kemble, actor, brother of Sarah Siddons (b. 1757)
1825
24 February - Thomas Bowdler, editor (b. 1754)
9 June - Abraham Rees, encyclopaedist (b. 1743)
10 August - Joseph Harris (Gomer), Baptist minister, poet and editor (b. 1773)
1827
date unknown - Helen Maria Williams, novelist and poet (b. c. 1761)
1828
September - William Madocks, landowner
1829
26 January - Benjamin Millingchamp, collector of manuscripts (b. 1756)
June - Elizabeth Randles, harpist (b. 1801)
1820s in Wales Wikipedia (Text) CC BY-SA