Why does a heart symbolise love?

A long time ago, humans thought that we felt with our hearts, and not our brains. It makes sense...throughout history (possibly the Egyptians) people thought that the heart was the center for emotions. Their hearts would race when they saw that special someone. Their hearts would drop with they heard bad news. Thus, them thinking that the heart was the center of emotion. And of course, love involves a LOT of emotion.