T.S. Eliot's The Waste Land Wiki

St. Magnus-the-Martyr

It is a Church of England church and parish in City of London, Lower Thames Street. Many authors had admired the beauty and location. The church was featured in Charles Dickens’ Oliver Twist, in the scene where Nancy secretly meet with Mr. Brownlow and Rose Maylie against Bill Sikes’ will, "the tower of old Saint Saviour's Church, and the spire of Saint Magnus, so long the giant-warders of the ancient bridge, were visible in the gloom." Eliot had celebrated the architecture and spiritual importance to him, quoting, “the interior of St. Magnus Martyr is to my mind one of the finest among Wren's interiors" Eliot came here as a sinner, and learn to appreciate its spirituality. 

St. Magnus- the- Martyr in The Waste Land[]

Line 263- 265

"Where the fishermen lounge at noon: where the walls

Of Magnus Martyr hold

Inexplicable splendor of Ionian white and gold." 

Here the interior of St. Magnus- the- Martyr is praised by Eliot. The "fishermen" is a reminder to an earlier allusion relating to the Athurian Legend of the Fischer King.