Shoes matter

If you get married and they only throw rice and confetti at you... you are lucky.
In England, during the Tudors' reign (when else?), they would throw shoes, old shoes, but always shoes. Rice and grains in general were meant to symbolize fertility and wealth, while it's debatable what shoes stood for. Mr. Panati in his Extraordinary Origins of Everyday Things suggests that shoes were a phallic symbol since ancient times and they had the same meaning as rice throwing. I am not totally sure about it since I learned it was Freud who tied them to sex, and particularly to female reproductive organs (shoes are hollow...).
The groom could also hit the bride with a shoe, to show his superiority and to mean she had become his ownership. Needless to say, this is now completely out of time: nowadays men just fall under female high heels&stilettos!