E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
The Persian Gulf; so called from a remarkable strip of water of a green colour along the Arabian coast.
Between 1690 and 1742 the 2nd Life Guards were facetiously called The Green Sea from their sea-green facings, in compliment to Queen Catharine, whose favourite colour it was. The facings of this regiment are now blue.