Celestial Blazon

I've seen upon the azure of the West
The clouds all silvery, purple, coppery, make
Great forms before the dazzled vision take
The shape of blazon splendently impressed.

An heraldic beast, for bearers or for crest,
Alerion, leopard, unicorn or snake—
Huge captive ones whose chains a gust might break—
Uprears its figure and outswells its breast.

In those strange combats in the vast of space
Of evil seraphs with the archangel race
A heavenly Baron must have won this shield—

Michael or George, perchance; 'tis blazed, I ween,
Like theirs who made Constantinople yield:
The sun, a gold bezant, on sea of green.