Seeing these hot 4.5 inch Vivienne Westwood skyscraper mules on sale  for $412 made us think that now is as good a time as any to take a quick look at the Louis heel. A “Louis heel,” like those seen on these mules, is a high heel with a concave curve (a curve that curves inward) in the middle.  The heel narrows in the middle and tapers outward at the bottom, making it more practical and comfortable than a straight stiletto but still sexy.

Louis heels (pronounced “Louie”) are named after France’s King Louis XIV (known as the Sun King). The king was a midget who would often wear high heels decorated with miniature battle scenes to make up for his lack of height (5′ 3″). King Louis famously decreed that only nobility could wear red-coloured heels and that nobody’s heels could be higher than his ones. Today Louis heels are also known as French heels.

Here’s another example of a Louis heel, also 4.5 inches high and also on sale from Zappos. This is the Stuart Weitzman Bandage heel, available in black or cola suede, for $199.