Life and cult
He was the Abbot of the Benedictine Abbey at Evesham, England, during the reign of King Offa of Mercia. His office is attested by charters in King Offa's reign, but no details of St Credan's life have been preserved.
Relics of St Credan at Evesham Abbey were put through an ordeal by fire in 1077, apparently because of Norman suspicion of this local saint, about whom little was known. The ordeal was conducted by the new Norman Abbot, Walter of Cerisy, who, after consultation with Archbishop Lanfranc, ordered a three-day fast, and had the seven penitential psalms and appropriate litanies chanted while the santity of the bones was tested by fire (see H E J Cowdrey's Lanfranc, p 177). According to legend, the relics not only survived, but shone like gold when moved to a place of devotion. This may, however, be a confusion with a similar account of the uncovering of St Credan's bones by Abbot Manny when his cult was originally developed. It is said that Abbot Manny "was frequently admonished in vision to take up the holy Abbot's relics and lay them in a shrine. When at length he came with great solemnity to do this, the body was found between two others, but distinguished from them by the great rightness with which it shone." (St Egwin and his Abbey of Evesham" 1904) 
The shrine established for St Credan by Abbot Walter of Cerisy in 1277 was one of only three to survive the destruction of the Abbey sanctuary when the tower of Evesham fell in 1207, and this was also thought to be miraculous (St Egwin and his Abbey of Evesham" 1904) 
St Credan of Cornwall
He is sometimes reputed to have founded the church of Sancreed in Cornwall, which is named for St Credan, but there were other Cornish saints of this name whose names may have been confused with his. A more likely candidate is St Credan of Cornwall, whose feastday is on 11 May. This is the St Credan who is said to have "killed by misfortune his own father, with which he was so moved as abandoning the world he became a hogherd, and lived so exemplary as he was after esteemed a saint" (Roscarrock, cited in Farmer )