It's Saint David's Day today, the national day of Wales which has been celebrated as such since the 12th century in honour of Wales' patron, Saint David (or Dewi Sant in Welsh).
David was born around the year 500 AD at Capel Non (Non's chapel) on the South-West Wales coast to a noble family. He became a priest and missionary, travelling around Wales and Britain, founding twelve monasteries as part of his strict monastic order -- including the great one at Glastonbury and one at Minevia, which is known known as St David's -- becoming most influential clergyman in all Wales.
David was named Archbishop of Wales in 550 and was canonised in 1120, very soon after which he was named Patron Saint of Wales.
David the Name:
The name David is Hebrew name, borne by one of the Bible's most notable kings. The origin of the name is obscure, but a popular theory is that it derives from Hebrew דוד (dwd) meaning "beloved".
However, David was not the saint's real name. He was actually named Dewi (or possibly Dewydd as a longer form) which was of native Celtic origin. David was simply used to "render" Dewi into English.
Dewi most likely derives from the Proto-Celtic *dŒwo "God" which became duiu in Old Welsh. It was not an uncommon element in Roman British names, and is also found in the Irish Dagda.
Thanks to St David's fame the name became prolific in Wales and spread around the British Isles, creating many forms. Dewi was used in the Middle Ages, then David took its place as Wales was Anglicised. David was in good use from the 12th century with the diminutive Daw(e), from which we get Dawson, and Davy.
The Welsh spelling of David is Dafydd, alongside the diminutives Dai, Deio and Taffy. [In fact, David was so common in Wales in the 18th and 19th centuries, "Taffy" became a byword in England for a Welshman, much like Paddy was a byword for an Irishman.
The many other British forms include Dàibhhead, Daithi (Irish), Dàibheid, Dàibhidh (Scottish) and Daveth (Cornish). Feminine forms include Davina, Davinia and Davida.
Fellow Welsh Saints:
St David lived in what is now called the "Age of Saints." The 5th and 6th centuries marked the establishment of many monastic orders by Celtic saints who often journeyed along all the western seaways between Brittany, Cornwall, Wales and Ireland to Christianise the Celtic world.
Aeddan - Aeddan of Ferns was a disciple of St David's who travelled to Ireland and founded a monastery at Ferns. His name is derived from Aedd (Aodh in Irish) meaning "fire."
Asaph - St Asaph (or Asa in Welsh) was a nephew and disciple of St Kentigern. The city of St Asaph is in North Wales.
Beuno - Also known as Bono, St Beuno was a 7th-century Welsh abbot, confessor, and saint. His name is possibly related to Berw, the Celtic god of bubbling springs and healing.
Brychan - Born in Ireland, Brychan is said to have moved to Wales as a child. A whole host of saintly children are attributed to his parentage including Cynog, Arthen, Berwyn, Arianwen, Meleri, Bethan and Endellion. His name derives from brych "speckled, freckled."
Cadoc - Known as one of Wales' greatest saints, St. Cadoc (or Cadog) the Wise was a 5th century bishop and martyr who established many churches in Wales, Cornwall, Scotland and Brittany. Cadoc is thought to be a diminutive of his birth name Cadfael, from cad "battle" and mael "prince."
Cadwaladr - Cadwaladr the Blessed was a 7th century king of Gwynedd. His name derives from cad "battle" and gwaladr "leader."
Cennydd - Anglicised as Kenneth, Cenydd was a 6th century Welsh hermit. His name is cognate with the Gaelic Cainneach, from cain "kind."
Collen - A 6th century Welsh misionary who founded sites in Brittany and Cornwall. In Welsh, collen means "hazel."
Eluned - St Eluned (e-LIN-ed), also known as Eiliwedd, Elyned, Almeda and Alud, was one of the many daughters of King Brychan. Her name is thought to derive from eilun "icon, image" and gwedd "appearance, form."
Gildas - A 6th century British monk who travelled around the Celtic world. His name derives from the Proto-Celtic *kilyo "companion" and *dŒwo "God."
Gwen - There are several St Gwens (also known as Wenna or Genuissa) including a daughter of Brychan. Gwen is the feminine form of gwyn "white, pure, blessed."
Gwenfrewi - Anglicised as Winifred, St Gwenfrewi was a niece of St Beuno and abbess of Trefynnon & Gwytherin. Her name is thought to derive from gwyn "blessed, pure" and Ffraid, the Welsh form of the Celtic goddess Brigantia.
Gwladys - One of the most notable daughters of Brychan, Gwladys (Gladys) married King Gwynllyw of Gwynllwg and was the mother of St Cadoc. The name could derive either from the Latin Claudia, or the Welsh gwlad "country, homeland."
Illtud - A 6th century abbott from Brittany who taught St David and St Gildas. His name derives from ill "many" and tud "people."
Madryn - Also known as Madrun, Materiana and Merthiana, St Madryn was a 5th century princess who ruled over her father's kingdom with her husband after his death. Her name most likely derives from Matrona, the Celtic mother goddess.
Melangell - Latinised as Monacella, was the daughter of an irish king who travelled to Wales to become a hermitess and later abbess of a religious community of women.
Non - Also known as Nonna or Nonita, St Non wa and the daughter of the chief of Minevia and the mother of St David. Her name derives from the Latin nonna "nun."
Seiriol - A son of King Owain Danwyn of Rhos and founder of the Penmon Priory. His name is possibly from siriol "cheerful."
Teilo - St Teilo was a disciple of St David who became Bishop of Llandeilo. His name possibly derives from the Old Welsh telu "retinue."