Analysis of A Roman's Chamber

I.
In the cave which wild weeds cover
Wait for thine aethereal lover;
For the pallid moon is waning,
O'er the spiral cypress hanging
And the moon no cloud is staining.

II.
It was once a Roman’s chamber,
Where he kept his darkest revels,
And the wild weeds twine and clamber;
It was then a chasm for devils.