Since no-one's got anywhere with this, apparently, I'll write down all the things I can think of, and we'll see if anyone can make sense of it.
How called the dwellers of Lyn-dun?
Great Homer's tale of Troy,
Or country of the midnight sun -
What doth all men Destroy?
Against it man hath dashed his foot,
This angel bears a spear!
In garden-glade where Lord Christ preyed
What spawns dark stars and fear?
This place the white Diana rose
Of this, Dido bereft;
Where on four leaves good fortune grows
East, west, south - what is Left?
The Corsican was vanquished there,
Elba? Or Waterloo?
Oh, mother of all sin!
Find green the same as shiretown's name,
Find Newgate Gaol, and win!