The site of WESTMINSTER ABBEY, and the ground immediately surrounding it, was anciently called Thorney Island, it having been " overgrown with thorns, and environed by water," prior to the foundation of the Minster or Church, from which it obtained its present appellation ; and it is a curious fact, that the outline of the Isle may still be traced, notwithstanding the numerous alterations which have taken place in this neighbourhood during the lapse of so many ages.

605: It is said [ Londiniana by Edward Wedlake Brayley] that the original foundation of Westminster Abbey was by Sebert, King of the East Saxons, who having been baptized by Mellitus, Bishop of London, about the year 604 or 605, immediately, to shew himself a Christian indeed, built a Church to the honour of God and St. Peter, on the west side of the Cittie of London.
But Bishop Mellitus was then done out of his episcopal rights [rites?] by no less than St Peter himself! [It is said].
And the ferryman was an ancestor of mine ["Edricus" = "Richard Eade", my brother's name! Well no one can say he wasn't my ancestor, which is as certain as you can get when dealing with stories like this] -

Saint Peter descended on the opposite shore, on a stormy night, and calling on Edricus, a Fisherman, desired to be ferried over to Thorney, which was then flooded round by heavy rains. Having promised, also, to reward him for his compliance, the Fisherman obeyed, and St. Peter entered the Church, whence a light immediately appeared to issue, of such transcendant brightness, as to convert the darkness of the night into meridian splendour.
The Apostle then proceeded to consecrate the fabric amidst a company of the heavenly host, and a chorus of celestial voices ; and whilst the most fragrant odours spread around, the wonders of the scene were augmented by angels, who were beheld ascending and descending as in Jacob's vision, recorded in the Old Testament.
The astonished Fisherman, awe-struck by the miraculous assemblage, was, for a while, lost in admiration ; but, at length, being restored to his powers by the Saint, he prepared to re-cross the river. On his return, St. Peter unfolded his sacred mission and character, and commanded Edricus to make known to Bishop Mellitus all that he had seen and heard, and to direct him to refrain from a second consecration.
The Fisherman, taking courage, required his promised reward, and St. Peter bidding him cast his nets into the water, repaid his services by a miraculous draught of salmon ; assuring him, that neither he nor any of his brethren should at any time want a supply of that kind of food, provided they made an offering of every tenth fish to the use of the newly consecrated Church: the Apostle then disappeared.
[Bishop Mellitus], therefore, desisted from proceeding in his appointed office, and in commemoration of the miracle, ordered the name of the place to be changed from Thorney to that of Westminster.
The belief of this legend was so successfully inculcated by the monks, that the offering of the tithe fish was frequently made by the Thames Fishermen, and even so late as the year 1382, that custom was still observed. Flete informs us that, in the year 1231, "there was a law-suit between the monks of Wesminster[sic] and the Minister of Rotherhithe, for the tithe of the Salmon caught in his parish ; the plea of the Monks being, that St. Peter had given them the tithe of all salmon caught in the Thames at the time he had consecrated their Church.

1578: Plan Of Part Of The City Of Westminster, Copied From Radulphus Aggas's Map, Taken In The Reign Of Queen Elizabeth, 1578.

Above Westminster Bridge

Westminster Hall and Abbey (no towers yet)

Westminster Abbey and the Thames, Samuel Scott, 1746

1792: Picturesque Views on the River Thames by Samuel Ireland -

Westminster Abbey and Bridge shown by Samuel Ireland 1792