St. David is the patron saint of Wales and his feast day (and possibly the date of his death) is March 1.  The Welsh spelling of his name is ‘Dafydd’ (Dah-vith). He is more commonly called Dewi, a derivative of Dafydd, by the Welsh.

St. David “died in the year 589. His father was the son of Ceredig, King of Ceredigion. After being educated in Cardiganshire, he went on pilgrimage through south Wales and the west of England, where it is said that he founded religious centres such as Glastonbury and Croyland. He even went on a pilgrimage to Jerusalem, where he was made archbishop.

He eventually settled at Glyn Rhosyn (St David’s), in south-west Wales, where he established a very strict ascetic religious community. Many miracles have been attributed to him, the most incredible of which was performed when he was preaching at the Synod of Llanddewibrefi – he caused the ground to rise underneath him so that he could be seen and heard by all. How much truth is in this account of his life by Rhigyfarch is hard to tell. It must be considered that Rhigyfarch was the son of the Bishop of St David’s, and that the Life was written as propaganda to establish Dewi’s superiority and defend the bishopric from being taken over by Canterbury and the Normans.”  http://www.museumwales.ac.uk/en/275/

“By the 9th century he had gained the name Aquaticus because he and the monks of his establishments were supposed to have drunk only water. His earliest Life* appeared around 1090 and was composed by a son of Sulien, bishop of St. David’s. The aim of this work was to promote the independence of the Welsh church. The Life tells us that St. David founded ten monasteries (including Glastonbury) and that the monks were vegetarian. Their regime included manual labour, study and worship.”  http://www.data-wales.co.uk/st_david.htm

“March 1, the date given by Rhygyfarch for the death of Dewi Sant (St. David), was celebrated as a religious festival up until the Protestant Reformation of the 16th century. In the 18th century it became a national festival among the Welsh, and continues as such to this day. The celebration usually entails singing and eating, which may mean a meal followed by singing, or much singing followed by a Te Bach, tea with teisen bach and bara brith. Y Ddraig Goch, the Red Dragon, is flown as a flag or worn as a pin or pendant, and leeks are worn, and sometimes eaten. In schools in Wales the boys take leeks to school, status being given to those who bring the biggest leeks, and eat them earliest in the day.”  http://www.davidmorgan.com/stdavid.html

“Many Welsh people wear one or both of the national emblems of Wales on their lapel to celebrate St. David: the daffodil (a generic Welsh symbol which is in season during March) or the leek (Saint David’s personal symbol) on this day. The leek arises from an occasion when a troop of Welsh were able to distinguish each other from a troop of English enemy dressed in similar fashion by wearing leeks.^[15] The association between leeks and daffodils is strengthened by the fact that they have similar names in Welsh, Cenhinen (leek) and Cenhinen Pedr (daffodil, literally “Peter’s leek”).”  http://en.wikipedia.org/wiki/Saint_David’s_Day

St David’s Day in 1244 was also the day the Gruffydd ap Llywelyn, son of Llywelyn Fawr, fell to his death when attempting to escape from a high window in the tower of London.