George Gordon Byron - On Chillon

Eternal Spirit of the chainless Mind!
Brightest in dungeons, Liberty, thou art;
For there thy habitation is the heart—
The heart which love of thee alone can bind;
And when thy sons to fetters are consigned,
- To fetters, and the damp vault's dayless gloom—
Their country conquers with their martyrdom,
And Freedom's fame finds wings on every wind.
Chillon! thy prison is a holy place,
And thy sad floor and altar, for 'twas trod,
Until his very steps have left a trace,
Worn, as if thy cold pavement were a sod,
By Bonnivard.—May none those marks efface!
For they appeal from tyranny to God.

George Gordon Byron

http://www.poemhunter.com/poem/on-chillon/