This is a variation of the "Armada" portrait of Queen Elizabeth of England.
Philip Mould has an excellent article about this portrait and portraits of Queen Elizabeth in general, parts of which are excerpted here, at this location.
"...The flamboyant image of Elizabeth seen here has become one of the most successful sovereign statements in English history. The contrast with Elizabeth’s earlier portraiture is striking. In the first portrait of her as Queen, the ‘Clopton’ portrait of 1558 [Private Collection, formerly Philip Mould Ltd], Elizabeth is shown with conspicuous piety. She wears a relatively simple black dress, and holds a religious book in her hand. This portrayal accords well with what we know to be Elizabeth’s virtuous, even frugal youthful character.But as her reign progressed Elizabeth’s portraiture became increasingly outré. Each portrait outdid the last with ever more elaborate changes in costume, pose, composition and jewelry, a progression matched by Elizabeth’s increasing addiction to expensive jewels. The process culminates in the over-indulgent, oversized, almost absurd example of the ‘Ditchley’ portrait [National Portrait Gallery], in which Elizabeth is shown full length, bestriding the earth, as bolts of lighting strike dramatically through the sky behind her. Her face is small, aged, even ugly, and overwhelmed by the rest of the painting. Elizabeth the person is subsumed by Elizabeth the icon...
And this was precisely the intention. They key to understanding Elizabeth’s portraiture lies in a recognition of her political vulnerability. Female monarchs in the sixteenth century were rare enough. Unmarried female monarchs were unheard of. Her image, therefore, could not stress traditional female charms; beauty, grace, fertility. In fact, it had to stress the opposite. From the late 1570s onwards, when it became clear that she would not marry, Elizabeth was effectively de-sexed. She was portrayed as a virtuous emblem of state, the Virgin Queen forsaking marriage for the good of the kingdom. It was therefore not enough for Elizabeth to rely on likeness alone in her portraiture. She certainly could not be portrayed in the demur, usually seated, manner of her sister Mary, supported as she was by her marriage to Philip of Spain. And, of course, Elizabeth was unable to rely on sheer physical presence in her portraits, as her father (had) done. Thus her portraits came to rely on bejewelled and bulky costumes – ‘Gloriana’ – for the projection of majesty. The production of Elizabeth’s portraits followed well established practices. A standardized face ‘mask’ was used, as has been the case in this example. Face masks not only saved time, but made up for the impossibility of painting the Queen from life for each new commission. Masks were also used to adhere to the fairly stringent, if unofficial, rules surrounding the production of the Queen’s image. She preferred, for example, to have no shadows across her face, and hence the stark, bright appearance of her features. The pose and costume would then have been painted with greater artistic freedom. Subtle changes would have been introduced in each portrait, usually in the accessories such as the fan in this example, so that the dependence on standard facial types did not give rise to identical portraits of the Queen. It appears to have been accepted that no two portraits of the Queen should be identical..."