It is said that Ely derives its name from 'eel' and '-y' or '-ey' meaning island, i.e. an island where there were a lot of eels. This may be true due to the position of Ely, an island in low lying fens, which were historically very marshy and rich in eels.
Ely cathedral was known as the Eye of the fen. The center. As Ely's surroundings were all march land as you said. The Isle Of Ely.
koopa90 4 years ago