It is most likely that the first people to realise the potential of the site at the mouth of the Tawe were the Vikings. Between the ninth and eleventh centuries, they harried the coasts of South Wales as marauders. But. they also visited these shores in a more peaceful guise as traders, and established a number of small commercial bases at points on the coast. Few tangible traces of Viking activities in this area remain, but the clearest testimony to the Norse presence is found in the many Scandinavian placenames which occur along the coast: e.g., Burry Holms, Sker, Worm's Head, and Swansea itself.

The name "Swansea" is probably derived from two Scandinavian elements, Sweyn, a personal name and ey, an "island" or "inlet." The island at the mouth of the Tawe has long since disappeared, if, indeed, there ever was one. Moreover, the precise identity of Sweyn is also uncertain. Sweyn was a fairly common Norse forename, but some local historians have sought to establish a connection with Sweyn Forkbeard, who was King of Denmark from 987-1014, and, briefly, King of England from 1013-14. He had undoubted links with South Wales, and was known to have been active in the Bristol Channel in 1002. If, indeed, it is his name which is commemorated in "Sweyn's Ey," then the foundation of Swansea must be ascribed to the beginning of the eleventh century.

 Several historians have chosen to believe that it was, in fact, Sweyn Forkbeard who founded Swansea, because then, in one sense, the town would have the prestige of having been a royal foundation. Unfortunately, this theory cannot be proved one way or the other. However, while no Viking remains have been found at Swansea, it is certain that a Scandinavian maritime trading post was set up there at the close of the dark ages, and that this established a commercial tradition which later attracted other invaders to the site.

There is no other evidence for the involvement of the vikings in the foundation of the town. Perhaps the best viewpoint is a cartoon by Dick German from A July 1912 edition of the South Wales Daily Post. The original was entitled 'What Scared Away Sweyne' The original caption read as follows:

'It has been supposed that the name of Swansea owes its origin to one Sweyne, a Danish marauder, who used the 'eye' or inlet as a safe landing place. Sweyne's unwelcome visits were soon discovered, and, needless to say, things were made so unpleasant for him that soon nothing remained but his name thanks to the several institutions for the prevention of invasion.'

Nothing changes does it?