The garter goes back to prehistoric times, with rock paintings depicting dancers wearing a garter. The garter also existed in Ancient Greece, where women slipped it on under their skirts to charm the male sex. In the Middle Ages it was more practical than aesthetic, being used to hold up men's hose and women's stockings.
But the tradition of wearing the garter actually comes from England. The Order of the Garter is one of the most important British orders of chivalry and one of the most prestigious in the world, considered to be the highest award for loyal service and military merit. The Order was created following a ball at which King Edward III of England danced with his lady-love, the Countess of Salisbury. The young Countess inadvertently let her garter drop. The gallant King is said to have picked it up and, to silence those who made fun of her, tied it around his own leg before declaring, "Messieurs, honni soit qui mal y pense" ("Shame on him who thinks evil of this"). He continued, "Those who are laughing now will be very honoured to wear one like this, for this ribbon will be held in such esteem that those who mock will themselves be eager to obtain one."
Today, the garter mainly symbolises purity and fidelity. In bygone times, the guests had to contribute financially to starting the newly-weds off in their married life, and so the bride would put her garter up for sale to the highest bidder. The higher went the bid, the higher rose the bride's dress. The winner had the honour of taking off the garter. This came about because the guests, long before wedding lists appeared, were expected to contribute financially to giving the newly-weds a start in life.