Seithenyn (sometimes spelt Seithennin) sometimes known as ''Seithenyn of the feeble mind'' is a figure from

Welsh Welsh may refer to: Related to Wales * Welsh, referring or related to Wales * Welsh language, a Brittonic Celtic language spoken in Wales * Welsh people People * Welsh (surname) * Sometimes used as a synonym for the ancient Britons (Celtic peopl ...

legend, apparently contemporary with King Gwyddno Garanhir. He is the protagonist of a poem in the Llyfr Du Caerfyrddin (Black Book of Carmarthen). According to legend, he was responsible for the sea-defences of

Cantre'r Gwaelod , also known as or ( en, The Lowland Hundred), is a legendary ancient sunken kingdom said to have occupied a tract of fertile land lying between Ramsey Island and Bardsey Island in what is now Cardigan Bay to the west of Wales. It has been ...

( en, The Lowland

Hundred 100 or one hundred (Roman numeral: C) is the natural number following 99 and preceding 101. In medieval contexts, it may be described as the short hundred or five score in order to differentiate the English and Germanic use of "hundred" to des ...

) or ''Maes Gwyddno'' ( en, the Plain of Gwyddno), in the kingdom of the legendary Gwyddno Garanhir, but neglected them one night because of his drunkenness. Because of this neglect, the sea overran it. Cantre'r Gwaelod is said to lie beneath the waters of

Cardigan Bay Cardigan Bay ( cy, Bae Ceredigion) is a large inlet of the Irish Sea, indenting the west coast of Wales between Bardsey Island, Gwynedd in the north, and Strumble Head, Pembrokeshire at its southern end. It is the largest bay in Wales. Geo ...

off the coast of

Ceredigion Ceredigion ( , , ) is a county in the west of Wales, corresponding to the historic county of Cardiganshire. During the second half of the first millennium Ceredigion was a minor kingdom. It has been administered as a county since 1282. Cer ...

near

Aberdyfi Aberdyfi (), also known as Aberdovey ( ), is a village and community in Gwynedd, Wales, located on the northern side of the estuary of the River Dyfi. The population of the community was 878 at the 2011 census. The electoral ward had a larg ...

Wales Wales ( cy, Cymru ) is a country that is part of the United Kingdom. It is bordered by England to the east, the Irish Sea to the north and west, the Celtic Sea to the south west and the Bristol Channel to the south. It had a population in ...

. Seithenyn (named in some later sources as being the son of Seithyn Saidi), was in charge of the embankment there, and as such, it was his failure to discharge his duties which led to its drowning. Seithenyn is also listed in the Triads of the Island of Britain as one of the ''Three Immortal Drunkards of the Isle of Britain''. The popular

Welsh saint Welsh may refer to: Related to Wales * Welsh, referring or related to Wales * Welsh language, a Brittonic Celtic language spoken in Wales * Welsh people People * Welsh (surname) * Sometimes used as a synonym for the ancient Britons (Celtic peopl ...

Saint Tudno Saint Tudno () is the patron saint of Llandudno (whose name is derived from his), and founder of the original parish church, located on the Great Orme peninsula. Origins Saint Tudno is said to have been one of the seven sons of King Seithenyn, ...

(founder and patron of

Llandudno Llandudno (, ) is a seaside resort, town and community in Conwy County Borough, Wales, located on the Creuddyn peninsula, which protrudes into the Irish Sea. In the 2011 UK census, the community – which includes Gogarth, Penrhyn Bay, Craig ...

) may have been Seithenyn's son. He appears as a character in

Thomas Love Peacock Thomas Love Peacock (18 October 1785 – 23 January 1866) was an English novelist, poet, and official of the East India Company. He was a close friend of Percy Bysshe Shelley and they influenced each other's work. Peacock wrote satirical novels, ...

's 1829 Arthurian novel '' The Misfortunes of Elphin''.

Sir John Rhys ''Sir'' is a formal honorific address in English for men, derived from Sire in the High Middle Ages. Both are derived from the old French "Sieur" (Lord), brought to England by the French-speaking Normans, and which now exist in French only as p ...

posited a connection between Seithenyn and the

Setantii The Setantii (sometimes read as ''Segantii'') were a possible pre-Roman British people who apparently lived in the western and southern littoral of Lancashire in England. It is thought likely they were a sept or sub-tribe of the Brigantes, who, at ...

, a

Celt The Celts (, see pronunciation for different usages) or Celtic peoples () are. "CELTS location: Greater Europe time period: Second millennium B.C.E. to present ancestry: Celtic a collection of Indo-European peoples. "The Celts, an ancient ...

ic tribe living in what is now the north west of

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe ...

.''Celtic Folklore: Welsh and Manx'' (1901), Ch. 6

Notes

References

*Rhys, John (1901).
Celtic Folklore: Welsh and Manx
' Medieval Welsh literature Welsh-language literature Welsh mythology {{Europe-myth-stub