Bishop and Confessor, patron of Wales. He is usually represented standing on a little hill, with a dove on his shoulder. From time immemorial the Welsh have worn a leek on St. David’s day, in memory of a battle against the Saxons, at which it is said they wore leeks in their hats, by St. David’s advice, to distinguish them from their enemies. He is commemorated on 1 March. The earliest mention of St. David is found in a tenth-century manuscript of the “Annales Cambriae”, which assigns his death to A.D. 601. Many other writers, from Geoffrey of Monmouth down to Father Richard Stanton, hold that he died about 544, but their opinion is based solely on data given in various late “lives” of St. David, and there seems no good reason for setting aside the definite statement of the “Annales Cambriae”, which is now generally accepted. Little else that can claim to be historical is known about St. David. The tradition that he was born at Henvynyw (Vetus-Menevia) in Cardiganshire is not improbable. He was prominent at the Synod of Brevi (Llandewi Brefi in Cardiganshire), which has been identified with the important Roman military station, Loventium. Shortly afterwards, in 569, he presided over another synod held at a place called Lucus Victoriae. He was Bishop (probably not Archbishop) of Menevia, the Roman port Menapia in Pembrokeshire, later known as St. David’s, then the chief point of departure for Ireland. St. David was canonized by Pope Callistus II in the year 1120.
As far as parades go, Cardiff, the capital of Wales, seems to have the largest. So large, in fact, that the British Monarch or the Prince of Wales attend. A variety of ingredients add to this celebration besides the parade. In recent years there have been special military ceremonies conducted by the Royal Welsh Regiment as well as food festivals and concerts.
St David’s Hall, a performing arts centre in the heart of Cardiff, stages a traditional concert on the evening of St David’s Day with the BBC National Orchestra of Wales, accompanied by the National Chorus of Wales and youth choruses.
On a smaller scale, many of the Welsh wear the traditional symbols of St David on their lapels in honour of the day: a daffodil or leek.
Information courtesy of Wikipedia and the Catholic Encyclopedia