Analysis of Lady, thy face is very beautiful

Lady, thy face is very beautiful,
A calm and stately beauty:  thy dark hair
Hangs as the passing winds paid homage there;
And gems, such gems as only princes cull
From earth's rich veins, are round thy neck and arm;
Ivory, with just one touch of colour warm;
And thy white robe floats queen-like, suiting well
A shape such as in ancient pictures dwell!
   If thou hadst lived in that old haunted time,
When sovereign Beauty was a thing sublime,
For which knights went to battle, and her glove
Had even more of glory than of love;—
Hadst thou lived in those days, how chivalrie,
With brand and banner, would have honour'd thee!
Then had this picture been a chronicle,
Of whose contents might only poets tell
What king had worn thy chains, what heroes sigh'd,
What thousands nameless, hopeless, for thee died.
But thou art of the Present--there is nought
About thee for the dreaming minstrel's thought,
Save vague imagination, which still lives
Upon the charmed light all beauty gives.
What hath romancing lute, or fancied line,
Or colour'd words to do with thee or thine?
No, the chords sleep in silence at thy feet,
They have no measures for thy music meet;
The poet hath no part in it, his dream
Would too much idleness of flattery seem;
And to that lovely picture only pays
The wordless homage of a lingering gaze.