With that failure and the final departure of the Legions, Regnum fell on evil days. Its position as the key to those harbours which had given it its importance now exposed it to the first raids of the pirates. These barbarians, according to legend, were Ella and his three sons, one of whom, Cissa, is said to have given Chichester her name--Cissa's camp, Cissa's Ceaster. Of Chichester's story during the Dark Ages we know as little as we know of most of the cities of England, but that it was destroyed utterly, as has been asserted, common sense refuses to allow us to believe. It certainly continued to exist, in barbarous fashion perhaps, but still to live, till with the conversion of the English it began to take on a new life, and with the Conquest was finally established as the seat of the Bishop. The apostle of the South Saxons, St Wilfrid, wrecked upon the flat and inhospitable shore of Selsey, was, as we know, their first bishop. He established his See, however, not at Chichester, but at Selsey where it remained until the Conqueror began to reorganise England upon a Roman plan, when more than one See was removed from the village in which it had long been established to the neighbouring great town. So it was with the Bishopric of Sussex, which in the first years of the Norman administration was removed from Selsey to Chichester. Thus Chichester was restored in 1075 to the great position it had held in the time of the Romans. Its lord was that Roger de Montgomery who received it from the Conqueror, together with more than eighty manors, and to him was due the castle which stood in the north-east quarter, and the rebuilding of the Roman walls, which continually renewed and rebuilt, still in some sort stand, upon Roman foundations, and mark the limits of the Roman town.