Proxy marriage is a wedding in which at least one of the lucky couple is absent, with a proxy filling in instead. It was fairly common amongst the nobility in the middle ages to engage in this practice. One intriguing instance that I have read is that between Philip II of Spain and Elizabeth of France, with the Duke of Alba acting as a proxy for the former. The process included a consummation in which Elizabeth and the Duke of Alba went to bed with one leg naked each and touched these legs against each other.
When and where did this practice originate? In the original case, what problem was it intended to solve? How long did it take for the practice to receive official or widespread recognition?