Helen of Troy, legends have it, was the most beautiful woman of her day who was the spark that set off the Trojan war. Actually it gets pretty complicated, as the Wikipedia link above indicates, but we'll go with the beautiful part.
Many artists over the years found it hard to resist the appeal of painting the most beautiful woman in the world, so "portraits" of Helen abound. A few are shown below along with some actresses who portrayed her in movies.
I find it interesting that Helen often seems to be a blonde or otherwise has light brown or red hair (Poynter's version is an exception). I've never gone nuts over blondes (though I have nothing against them). But the artists who did choose to depict her as blonde almost surely had that preference.
What we have here is a demonstration of subjectivity in art. Clearly the casting directors and painters strained to select an appearance that was to represent the ultimate in female beauty. (Okay, I'm not so sure about Sandy's scowling redhead.) Yet these Helens differ. And even though they differ, there's not one I'd be inclined to abduct and haul off to Troy. However, if she had dark hair and gray eyes ....