The fact was pointed out by two separate Twitter account recently and now that you mention it, it’s rather obvious.
While some reports claim the pair were the same height, standing at 1.78m, other say Charles was in fact slightly taller, 5 feet 11 inches to Diana’s 5 feet 10 inches.
Sociologist and author Phillip N. Cohen, who pointed out the difference on Twitter, says in his book The Family: Diversity, Inequality, and Social Change that the image of the taller husband “conjures up images of the protective, dominant man”.
“Although Charles was actually 1 inch taller than Diana, he often looked shorter than her in candid pictures,” writes Cohen. “But when they posed for portraits, he usually stood on a box or step, as in the picture for the stamp commemorating their royal wedding.”
Whatever the reason it will remain a royal mystery....